Fix memory issues in BIO_*printf functions
The internal |fmtstr| function used in processing a "%s" format string in the BIO_*printf functions could overflow while calculating the length of a string and cause an OOB read when printing very long strings. Additionally the internal |doapr_outch| function can attempt to write to an OOB memory location (at an offset from the NULL pointer) in the event of a memory allocation failure. In 1.0.2 and below this could be caused where the size of a buffer to be allocated is greater than INT_MAX. E.g. this could be in processing a very long "%s" format string. Memory leaks can also occur. These issues will only occur on certain platforms where sizeof(size_t) > sizeof(int). E.g. many 64 bit systems. The first issue may mask the second issue dependent on compiler behaviour. These problems could enable attacks where large amounts of untrusted data is passed to the BIO_*printf functions. If applications use these functions in this way then they could be vulnerable. OpenSSL itself uses these functions when printing out human-readable dumps of ASN.1 data. Therefore applications that print this data could be vulnerable if the data is from untrusted sources. OpenSSL command line applications could also be vulnerable where they print out ASN.1 data, or if untrusted data is passed as command line arguments. Libssl is not considered directly vulnerable. Additionally certificates etc received via remote connections via libssl are also unlikely to be able to trigger these issues because of message size limits enforced within libssl. CVE-2016-0799 Issue reported by Guido Vranken. Reviewed-by: Andy Polyakov <appro@openssl.org>
This commit is contained in:
Matt Caswell
parent
069c3c0908
commit
9cb177301f
1 changed files with 116 additions and 71 deletions
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@ -124,14 +124,14 @@
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# define LLONG long
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#endif
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static void fmtstr(char **, char **, size_t *, size_t *,
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static int fmtstr(char **, char **, size_t *, size_t *,
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const char *, int, int, int);
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static void fmtint(char **, char **, size_t *, size_t *,
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static int fmtint(char **, char **, size_t *, size_t *,
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LLONG, int, int, int, int);
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static void fmtfp(char **, char **, size_t *, size_t *,
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static int fmtfp(char **, char **, size_t *, size_t *,
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LDOUBLE, int, int, int);
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static void doapr_outch(char **, char **, size_t *, size_t *, int);
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static void _dopr(char **sbuffer, char **buffer,
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static int doapr_outch(char **, char **, size_t *, size_t *, int);
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static int _dopr(char **sbuffer, char **buffer,
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size_t *maxlen, size_t *retlen, int *truncated,
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const char *format, va_list args);
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@ -164,7 +164,7 @@ static void _dopr(char **sbuffer, char **buffer,
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#define char_to_int(p) (p - '0')
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#define OSSL_MAX(p,q) ((p >= q) ? p : q)
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static void
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static int
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_dopr(char **sbuffer,
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char **buffer,
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size_t *maxlen,
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@ -195,7 +195,8 @@ _dopr(char **sbuffer,
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if (ch == '%')
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state = DP_S_FLAGS;
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else
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doapr_outch(sbuffer, buffer, &currlen, maxlen, ch);
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if(!doapr_outch(sbuffer, buffer, &currlen, maxlen, ch))
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return 0;
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ch = *format++;
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break;
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case DP_S_FLAGS:
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@ -301,8 +302,9 @@ _dopr(char **sbuffer,
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value = va_arg(args, int);
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break;
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}
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fmtint(sbuffer, buffer, &currlen, maxlen,
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value, 10, min, max, flags);
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if (!fmtint(sbuffer, buffer, &currlen, maxlen, value, 10, min,
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max, flags))
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return 0;
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break;
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case 'X':
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flags |= DP_F_UP;
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@ -325,17 +327,19 @@ _dopr(char **sbuffer,
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value = (LLONG) va_arg(args, unsigned int);
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break;
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}
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fmtint(sbuffer, buffer, &currlen, maxlen, value,
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if (!fmtint(sbuffer, buffer, &currlen, maxlen, value,
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ch == 'o' ? 8 : (ch == 'u' ? 10 : 16),
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min, max, flags);
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min, max, flags))
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return 0;
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break;
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case 'f':
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if (cflags == DP_C_LDOUBLE)
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fvalue = va_arg(args, LDOUBLE);
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else
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fvalue = va_arg(args, double);
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fmtfp(sbuffer, buffer, &currlen, maxlen,
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fvalue, min, max, flags);
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if (!fmtfp(sbuffer, buffer, &currlen, maxlen, fvalue, min, max,
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flags))
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return 0;
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break;
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case 'E':
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flags |= DP_F_UP;
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@ -354,8 +358,9 @@ _dopr(char **sbuffer,
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fvalue = va_arg(args, double);
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break;
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case 'c':
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doapr_outch(sbuffer, buffer, &currlen, maxlen,
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va_arg(args, int));
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if(!doapr_outch(sbuffer, buffer, &currlen, maxlen,
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va_arg(args, int)))
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return 0;
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break;
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case 's':
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strvalue = va_arg(args, char *);
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@ -365,13 +370,15 @@ _dopr(char **sbuffer,
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else
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max = *maxlen;
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}
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fmtstr(sbuffer, buffer, &currlen, maxlen, strvalue,
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flags, min, max);
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if (!fmtstr(sbuffer, buffer, &currlen, maxlen, strvalue,
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flags, min, max))
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return 0;
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break;
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case 'p':
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value = (size_t)va_arg(args, void *);
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fmtint(sbuffer, buffer, &currlen, maxlen,
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value, 16, min, max, flags | DP_F_NUM);
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if (!fmtint(sbuffer, buffer, &currlen, maxlen,
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value, 16, min, max, flags | DP_F_NUM))
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return 0;
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break;
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case 'n': /* XXX */
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if (cflags == DP_C_SHORT) {
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@ -393,7 +400,8 @@ _dopr(char **sbuffer,
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}
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break;
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case '%':
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doapr_outch(sbuffer, buffer, &currlen, maxlen, ch);
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if(!doapr_outch(sbuffer, buffer, &currlen, maxlen, ch))
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return 0;
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break;
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case 'w':
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/* not supported yet, treat as next char */
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@ -417,46 +425,56 @@ _dopr(char **sbuffer,
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*truncated = (currlen > *maxlen - 1);
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if (*truncated)
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currlen = *maxlen - 1;
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doapr_outch(sbuffer, buffer, &currlen, maxlen, '\0');
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if(!doapr_outch(sbuffer, buffer, &currlen, maxlen, '\0'))
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return 0;
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*retlen = currlen - 1;
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return;
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return 1;
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}
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static void
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static int
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fmtstr(char **sbuffer,
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char **buffer,
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size_t *currlen,
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size_t *maxlen, const char *value, int flags, int min, int max)
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{
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int padlen, strln;
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int padlen;
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size_t strln;
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int cnt = 0;
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if (value == 0)
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value = "<NULL>";
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for (strln = 0; value[strln]; ++strln) ;
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strln = strlen(value);
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if (strln > INT_MAX)
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strln = INT_MAX;
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padlen = min - strln;
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if (padlen < 0)
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if (min < 0 || padlen < 0)
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padlen = 0;
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if (flags & DP_F_MINUS)
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padlen = -padlen;
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while ((padlen > 0) && (cnt < max)) {
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doapr_outch(sbuffer, buffer, currlen, maxlen, ' ');
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if(!doapr_outch(sbuffer, buffer, currlen, maxlen, ' '))
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return 0;
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--padlen;
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++cnt;
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}
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while (*value && (cnt < max)) {
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doapr_outch(sbuffer, buffer, currlen, maxlen, *value++);
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if(!doapr_outch(sbuffer, buffer, currlen, maxlen, *value++))
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return 0;
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++cnt;
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}
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while ((padlen < 0) && (cnt < max)) {
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doapr_outch(sbuffer, buffer, currlen, maxlen, ' ');
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if(!doapr_outch(sbuffer, buffer, currlen, maxlen, ' '))
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return 0;
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++padlen;
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++cnt;
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}
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return 1;
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}
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static void
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static int
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fmtint(char **sbuffer,
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char **buffer,
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size_t *currlen,
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@ -516,37 +534,44 @@ fmtint(char **sbuffer,
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/* spaces */
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while (spadlen > 0) {
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doapr_outch(sbuffer, buffer, currlen, maxlen, ' ');
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if(!doapr_outch(sbuffer, buffer, currlen, maxlen, ' '))
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return 0;
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--spadlen;
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}
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/* sign */
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if (signvalue)
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doapr_outch(sbuffer, buffer, currlen, maxlen, signvalue);
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if(!doapr_outch(sbuffer, buffer, currlen, maxlen, signvalue))
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return 0;
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/* prefix */
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while (*prefix) {
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doapr_outch(sbuffer, buffer, currlen, maxlen, *prefix);
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if(!doapr_outch(sbuffer, buffer, currlen, maxlen, *prefix))
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return 0;
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prefix++;
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}
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/* zeros */
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if (zpadlen > 0) {
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while (zpadlen > 0) {
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doapr_outch(sbuffer, buffer, currlen, maxlen, '0');
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if(!doapr_outch(sbuffer, buffer, currlen, maxlen, '0'))
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return 0;
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--zpadlen;
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}
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}
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/* digits */
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while (place > 0)
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doapr_outch(sbuffer, buffer, currlen, maxlen, convert[--place]);
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while (place > 0) {
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if (!doapr_outch(sbuffer, buffer, currlen, maxlen, convert[--place]))
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return 0;
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}
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/* left justified spaces */
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while (spadlen < 0) {
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doapr_outch(sbuffer, buffer, currlen, maxlen, ' ');
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if (!doapr_outch(sbuffer, buffer, currlen, maxlen, ' '))
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return 0;
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++spadlen;
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}
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return;
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return 1;
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}
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static LDOUBLE abs_val(LDOUBLE value)
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@ -577,7 +602,7 @@ static long roundv(LDOUBLE value)
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return intpart;
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}
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static void
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static int
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fmtfp(char **sbuffer,
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char **buffer,
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size_t *currlen,
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@ -656,47 +681,61 @@ fmtfp(char **sbuffer,
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if ((flags & DP_F_ZERO) && (padlen > 0)) {
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if (signvalue) {
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doapr_outch(sbuffer, buffer, currlen, maxlen, signvalue);
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if (!doapr_outch(sbuffer, buffer, currlen, maxlen, signvalue))
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return 0;
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--padlen;
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signvalue = 0;
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}
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while (padlen > 0) {
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doapr_outch(sbuffer, buffer, currlen, maxlen, '0');
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if (!doapr_outch(sbuffer, buffer, currlen, maxlen, '0'))
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return 0;
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--padlen;
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}
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}
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while (padlen > 0) {
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doapr_outch(sbuffer, buffer, currlen, maxlen, ' ');
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if (!doapr_outch(sbuffer, buffer, currlen, maxlen, ' '))
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return 0;
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--padlen;
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}
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if (signvalue)
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doapr_outch(sbuffer, buffer, currlen, maxlen, signvalue);
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if (signvalue && !doapr_outch(sbuffer, buffer, currlen, maxlen, signvalue))
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return 0;
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while (iplace > 0)
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doapr_outch(sbuffer, buffer, currlen, maxlen, iconvert[--iplace]);
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while (iplace > 0) {
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if (!doapr_outch(sbuffer, buffer, currlen, maxlen, iconvert[--iplace]))
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return 0;
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}
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/*
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* Decimal point. This should probably use locale to find the correct
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* char to print out.
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*/
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if (max > 0 || (flags & DP_F_NUM)) {
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doapr_outch(sbuffer, buffer, currlen, maxlen, '.');
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if (!doapr_outch(sbuffer, buffer, currlen, maxlen, '.'))
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return 0;
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while (fplace > 0)
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doapr_outch(sbuffer, buffer, currlen, maxlen, fconvert[--fplace]);
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while (fplace > 0) {
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if(!doapr_outch(sbuffer, buffer, currlen, maxlen,
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fconvert[--fplace]))
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return 0;
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}
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}
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while (zpadlen > 0) {
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doapr_outch(sbuffer, buffer, currlen, maxlen, '0');
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if (!doapr_outch(sbuffer, buffer, currlen, maxlen, '0'))
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return 0;
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--zpadlen;
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}
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while (padlen < 0) {
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doapr_outch(sbuffer, buffer, currlen, maxlen, ' ');
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if (!doapr_outch(sbuffer, buffer, currlen, maxlen, ' '))
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return 0;
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++padlen;
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}
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return 1;
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}
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static void
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#define BUFFER_INC 1024
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static int
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doapr_outch(char **sbuffer,
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char **buffer, size_t *currlen, size_t *maxlen, int c)
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{
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@ -707,24 +746,25 @@ doapr_outch(char **sbuffer,
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assert(*currlen <= *maxlen);
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if (buffer && *currlen == *maxlen) {
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*maxlen += 1024;
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if (*maxlen > INT_MAX - BUFFER_INC)
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return 0;
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*maxlen += BUFFER_INC;
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if (*buffer == NULL) {
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*buffer = OPENSSL_malloc(*maxlen);
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if (*buffer == NULL) {
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/* Panic! Can't really do anything sensible. Just return */
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return;
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}
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if (*buffer == NULL)
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return 0;
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if (*currlen > 0) {
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assert(*sbuffer != NULL);
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memcpy(*buffer, *sbuffer, *currlen);
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}
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*sbuffer = NULL;
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} else {
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*buffer = OPENSSL_realloc(*buffer, *maxlen);
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if (!*buffer) {
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/* Panic! Can't really do anything sensible. Just return */
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return;
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}
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char *tmpbuf;
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tmpbuf = OPENSSL_realloc(*buffer, *maxlen);
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if (tmpbuf == NULL)
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return 0;
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*buffer = tmpbuf;
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}
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}
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@ -735,7 +775,7 @@ doapr_outch(char **sbuffer,
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(*buffer)[(*currlen)++] = (char)c;
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}
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return;
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return 1;
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}
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/***************************************************************************/
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@ -766,7 +806,11 @@ int BIO_vprintf(BIO *bio, const char *format, va_list args)
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int ignored;
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dynbuf = NULL;
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_dopr(&hugebufp, &dynbuf, &hugebufsize, &retlen, &ignored, format, args);
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if (!_dopr(&hugebufp, &dynbuf, &hugebufsize, &retlen, &ignored, format,
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args)) {
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OPENSSL_free(dynbuf);
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return -1;
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}
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if (dynbuf) {
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ret = BIO_write(bio, dynbuf, (int)retlen);
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OPENSSL_free(dynbuf);
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@ -800,7 +844,8 @@ int BIO_vsnprintf(char *buf, size_t n, const char *format, va_list args)
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size_t retlen;
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int truncated;
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_dopr(&buf, NULL, &n, &retlen, &truncated, format, args);
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if(!_dopr(&buf, NULL, &n, &retlen, &truncated, format, args))
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return -1;
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if (truncated)
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/*
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