[alsa-devel] [PATCH] SOUND: usb/endpoint, fix dangling pointer use
Stanse found that in snd_usb_parse_audio_endpoints, there is a dangling pointer dereference. When snd_usb_parse_audio_format fails, fp is freed, and continue invoked. On the next loop, there is "fp && fp->altsetting == 1 && fp->channels == 1" test, but fp is set from the last iteration (but is bogus) and thus ilegally dereferenced.
Set fp to NULL before "continue".
Signed-off-by: Jiri Slaby jslaby@suse.cz Cc: Daniel Mack daniel@caiaq.de Cc: Clemens Ladisch clemens@ladisch.de Cc: Takashi Iwai tiwai@suse.de --- sound/usb/endpoint.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c index 9593b91..6f6596c 100644 --- a/sound/usb/endpoint.c +++ b/sound/usb/endpoint.c @@ -427,6 +427,7 @@ int snd_usb_parse_audio_endpoints(struct snd_usb_audio *chip, int iface_no) if (snd_usb_parse_audio_format(chip, fp, format, fmt, stream, alts) < 0) { kfree(fp->rate_table); kfree(fp); + fp = NULL; continue; }
On Mon, Jun 21, 2010 at 05:03:21PM +0200, Jiri Slaby wrote:
Stanse found that in snd_usb_parse_audio_endpoints, there is a dangling pointer dereference. When snd_usb_parse_audio_format fails, fp is freed, and continue invoked. On the next loop, there is "fp && fp->altsetting == 1 && fp->channels == 1" test, but fp is set from the last iteration (but is bogus) and thus ilegally dereferenced.
Set fp to NULL before "continue".
Oh, absolutely. Thanks.
Signed-off-by: Jiri Slaby jslaby@suse.cz
Acked-by: Daniel Mack daniel@caiaq.de
I think this should go thru the ALSA tree.
Daniel
Cc: Clemens Ladisch clemens@ladisch.de Cc: Takashi Iwai tiwai@suse.de
sound/usb/endpoint.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c index 9593b91..6f6596c 100644 --- a/sound/usb/endpoint.c +++ b/sound/usb/endpoint.c @@ -427,6 +427,7 @@ int snd_usb_parse_audio_endpoints(struct snd_usb_audio *chip, int iface_no) if (snd_usb_parse_audio_format(chip, fp, format, fmt, stream, alts) < 0) { kfree(fp->rate_table); kfree(fp);
fp = NULL; continue;-- 1.7.1
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At Mon, 21 Jun 2010 17:05:16 +0200, Daniel Mack wrote:
On Mon, Jun 21, 2010 at 05:03:21PM +0200, Jiri Slaby wrote:
Stanse found that in snd_usb_parse_audio_endpoints, there is a dangling pointer dereference. When snd_usb_parse_audio_format fails, fp is freed, and continue invoked. On the next loop, there is "fp && fp->altsetting == 1 && fp->channels == 1" test, but fp is set from the last iteration (but is bogus) and thus ilegally dereferenced.
Set fp to NULL before "continue".
Oh, absolutely. Thanks.
Signed-off-by: Jiri Slaby jslaby@suse.cz
Acked-by: Daniel Mack daniel@caiaq.de
I think this should go thru the ALSA tree.
Yep, I applied it now. Thanks!
Takashi
participants (3)
-
Daniel Mack -
Jiri Slaby -
Takashi Iwai