diff options
| author | Al Viro <viro@ftp.linux.org.uk> | 2008-05-21 00:30:41 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@infradead.org> | 2008-06-05 06:35:47 -0300 |
| commit | a230e55d92347e09d9ba2e97096df114b2dfaf2d (patch) | |
| tree | 757a051bf453b408a64ae33bbb5aaea352e15e9d /drivers | |
| parent | f34ec12a17984d7df784bf49caf64f5f743e5e10 (diff) | |
V4L/DVB (7957): fix the roothole in av7110_av.c
direct dereferencing from user-supplied address
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Oliver Endriss <o.endriss@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/media/dvb/ttpci/av7110_av.c | 34 |
1 files changed, 27 insertions, 7 deletions
diff --git a/drivers/media/dvb/ttpci/av7110_av.c b/drivers/media/dvb/ttpci/av7110_av.c index 3e6b650fbb81..ec55a968f204 100644 --- a/drivers/media/dvb/ttpci/av7110_av.c +++ b/drivers/media/dvb/ttpci/av7110_av.c @@ -965,8 +965,9 @@ static u8 iframe_header[] = { 0x00, 0x00, 0x01, 0xe0, 0x00, 0x00, 0x80, 0x00, 0x static int play_iframe(struct av7110 *av7110, char __user *buf, unsigned int len, int nonblock) { - int i, n; + unsigned i, n; int progressive = 0; + int match = 0; dprintk(2, "av7110:%p, \n", av7110); @@ -975,12 +976,31 @@ static int play_iframe(struct av7110 *av7110, char __user *buf, unsigned int len return -EBUSY; } - for (i = 0; i < len - 5; i++) { - /* get progressive flag from picture extension */ - if (buf[i] == 0x00 && buf[i+1] == 0x00 && - buf[i+2] == 0x01 && (unsigned char)buf[i+3] == 0xb5 && - (buf[i+4] & 0xf0) == 0x10) - progressive = buf[i+5] & 0x08; + /* search in buf for instances of 00 00 01 b5 1? */ + for (i = 0; i < len; i++) { + unsigned char c; + if (get_user(c, buf + i)) + return -EFAULT; + if (match == 5) { + progressive = c & 0x08; + match = 0; + } + if (c == 0x00) { + match = (match == 1 || match == 2) ? 2 : 1; + continue; + } + switch (match++) { + case 2: if (c == 0x01) + continue; + break; + case 3: if (c == 0xb5) + continue; + break; + case 4: if ((c & 0xf0) == 0x10) + continue; + break; + } + match = 0; } /* setting n always > 1, fixes problems when playing stillframes |