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gpg: Fix verification of cleartext signatures with overlong lines.

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* g10/armor.c (fake_packet): Indicate truncated lines by inserting a
formfeed.
(armor_filter): Replace assert by log_assert.
--

Reported-by: Demi Marie Obenour
GnuPG-bug-id: T6272
This commit is contained in:
Werner Koch 2022-11-10 14:50:21 +01:00
parent 8afa9735a6
commit 976e9d6083
No known key found for this signature in database
GPG Key ID: E3FDFF218E45B72B
1 changed files with 24 additions and 5 deletions
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29
g10/armor.c
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@ -650,6 +650,7 @@ fake_packet( armor_filter_context_t *afx, IOBUF a,
byte *p;
byte tempbuf[PARTIAL_CHUNK];
size_t tempbuf_len=0;
int this_truncated;
while( !rc && size-len>=(PARTIAL_CHUNK+1)) {
/* copy what we have in the line buffer */
@ -684,7 +685,13 @@ fake_packet( armor_filter_context_t *afx, IOBUF a,
continue;
}
if( !maxlen )
{
afx->truncated++;
this_truncated = 1;
}
else
this_truncated = 0;
p = afx->buffer;
n = afx->buffer_len;
@ -737,7 +744,7 @@ fake_packet( armor_filter_context_t *afx, IOBUF a,
}
/* Now handle the end-of-line canonicalization */
if( !afx->not_dash_escaped )
if( !afx->not_dash_escaped || this_truncated)
{
int crlf = n > 1 && p[n-2] == '\r' && p[n-1]=='\n';
@ -754,10 +761,17 @@ fake_packet( armor_filter_context_t *afx, IOBUF a,
* or calculate the hash here in this module and somehow find
* a way to send the hash down the processing line (well, a special
* faked packet could do the job).
*
* To make sure that a truncated line triggers a bad
* signature error we replace a removed LF by a FF or
* append a FF. Right, this is a hack but better than a
* global variable and way easier than to introduce a new
* control packet or insert a line like "[truncated]\n"
* into the filter output.
*/
if( crlf )
afx->buffer[afx->buffer_len++] = '\r';
afx->buffer[afx->buffer_len++] = '\n';
afx->buffer[afx->buffer_len++] = this_truncated? '\f':'\n';
afx->buffer[afx->buffer_len] = '\0';
}
}
@ -1126,11 +1140,11 @@ radix64_read( armor_filter_context_t *afx, IOBUF a, size_t *retn,
rc = 0;
else if( rc == 2 ) {
log_error(_("premature eof (in trailer)\n"));
rc = GPG_ERR_INVALID_ARMOR;
rc = GPG_ERR_INV_ARMOR;
}
else {
log_error(_("error in trailer line\n"));
rc = GPG_ERR_INVALID_ARMOR;
rc = GPG_ERR_INV_ARMOR;
}
#endif
}
@ -1278,7 +1292,7 @@ armor_filter( void *opaque, int control,
if( !fp ) {
fp = fopen("armor.out", "w");
assert(fp);
log_assert(fp);
}
#endif
@ -1539,6 +1553,11 @@ armor_filter( void *opaque, int control,
afx->no_openpgp_data = 1;
write_status_text( STATUS_NODATA, "1" );
}
/* Note that in a cleartext signature truncated lines in the
* plaintext are detected and propagated to the signature
* checking code by inserting a \f into the plaintext. We do
* not use log_info here because some of the truncated lines
* are harmless. */
if( afx->truncated )
log_info(_("invalid armor: line longer than %d characters\n"),
MAX_LINELEN );