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gpg: Detect already compressed data also when using a pipe.

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* common/iobuf.c (file_filter_ctx_t): Add fields for the peek feature.
(file_filter): Implement peeking.
(iobuf_ioctl): Add new IOBUF_IOCTL_PEEK.
* common/iobuf.h (IOBUF_IOCTL_PEEK, IOBUFCTRL_PEEK): New.
* common/miscellaneous.c (is_file_compressed): Rewrite.  Detect PDF.
* g10/encrypt.c (encrypt_simple): Peek before detecting compression.
(encrypt_crypt): Ditto.
* g10/sign.c (sign_file): Also detect already compressed data.

* g10/options.h (opt): Add explicit_compress_option.
* g10/gpg.c (main): Set opt.explicit_compress_option for -z.

--

Note that this patch also introduces a compression check for signing
which was never done in the past.

GnuPG-bug-id: 6332
This commit is contained in:
Werner Koch 2023-01-18 18:04:50 +01:00
parent 94ae43be36
commit 60963d98cf
No known key found for this signature in database
GPG key ID: E3FDFF218E45B72B
9 changed files with 201 additions and 64 deletions
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77
common/miscellaneous.c
View file

@ -418,7 +418,7 @@ decode_c_string (const char *src)
/* Check whether (BUF,LEN) is valid header for an OpenPGP compressed
* packet. LEN should be at least 6. */
static int
is_openpgp_compressed_packet (unsigned char *buf, size_t len)
is_openpgp_compressed_packet (const unsigned char *buf, size_t len)
{
int c, ctb, pkttype;
int lenbytes;
@ -460,63 +460,46 @@ is_openpgp_compressed_packet (unsigned char *buf, size_t len)
/*
* Check if the file is compressed.
* Check if the file is compressed. You need to pass the first bytes
* of the file as (BUF,BUFLEN). Returns true if the buffer seems to
* be compressed.
*/
int
is_file_compressed (const char *s, int *ret_rc)
is_file_compressed (const byte *buf, unsigned int buflen)
{
iobuf_t a;
byte buf[6];
int i;
int rc = 0;
int overflow;
int i;
struct magic_compress_s {
size_t len;
byte magic[4];
} magic[] = {
{ 3, { 0x42, 0x5a, 0x68, 0x00 } }, /* bzip2 */
{ 3, { 0x1f, 0x8b, 0x08, 0x00 } }, /* gzip */
{ 4, { 0x50, 0x4b, 0x03, 0x04 } }, /* (pk)zip */
};
struct magic_compress_s
{
byte len;
byte magic[5];
} magic[] =
{
{ 3, { 0x42, 0x5a, 0x68, 0x00 } }, /* bzip2 */
{ 3, { 0x1f, 0x8b, 0x08, 0x00 } }, /* gzip */
{ 4, { 0x50, 0x4b, 0x03, 0x04 } }, /* (pk)zip */
{ 5, { '%', 'P', 'D', 'F', '-'} } /* PDF */
};
if ( iobuf_is_pipe_filename (s) || !ret_rc )
return 0; /* We can't check stdin or no file was given */
a = iobuf_open( s );
if ( a == NULL ) {
*ret_rc = gpg_error_from_syserror ();
return 0;
}
iobuf_ioctl (a, IOBUF_IOCTL_NO_CACHE, 1, NULL);
if ( iobuf_get_filelength( a, &overflow ) < 6 && !overflow) {
*ret_rc = 0;
goto leave;
if ( buflen < 6 )
{
return 0; /* Too short to check - assume uncompressed. */
}
if ( iobuf_read( a, buf, 6 ) == -1 ) {
*ret_rc = a->error;
goto leave;
}
for ( i = 0; i < DIM( magic ); i++ ) {
if ( !memcmp( buf, magic[i].magic, magic[i].len ) ) {
*ret_rc = 0;
rc = 1;
goto leave;
for ( i = 0; i < DIM (magic); i++ )
{
if ( !memcmp( buf, magic[i].magic, magic[i].len ))
{
return 1; /* Is compressed. */
}
}
if (is_openpgp_compressed_packet (buf, 6))
{
*ret_rc = 0;
rc = 1;
}
if (buflen >= 6 && is_openpgp_compressed_packet (buf, buflen))
{
return 1; /* Already compressed. */
}
leave:
iobuf_close( a );
return rc;
return 0; /* Not detected as compressed. */
}