| Message ID | 201609042115.47744.cehoyos@ag.or.at |
|---|---|
| State | Accepted |
| Commit | f077ad69c682c13ab75a72aec11a61cac53f0c91 |
| Headers | show |
Le nonidi 19 fructidor, an CCXXIV, Carl Eugen Hoyos a écrit : > From a3dcd65c313e6b456fcb05915508d8d583c1840e Mon Sep 17 00:00:00 2001 > From: Carl Eugen Hoyos <cehoyos@ag.or.at> > Date: Sun, 4 Sep 2016 21:11:02 +0200 > Subject: [PATCH] lavc/avpacket: Fix undefined behaviour, do not pass a null > pointer to memcpy(). I read the spec for memcpy(), passing NULL is not stated as an undefined behaviour if the size if 0. UBSan seems to be reporting a false positive. I do not object to the patch, but the commit message could state the bug is not ours. Regards,
2016-09-04 21:24 GMT+02:00 Nicolas George <george@nsup.org>: >> Subject: [PATCH] lavc/avpacket: Fix undefined behaviour, >> do not pass a null pointer to memcpy(). > > I read the spec for memcpy(), passing NULL is not stated as an > undefined behaviour if the size if 0. UBSan seems to be > reporting a false positive. This site claims that ISO disagrees: http://stackoverflow.com/questions/5243012/is-it-guaranteed-to-be-safe-to-perform-memcpy0-0-0 (No opinion whatsoever here, just a ticket.) Carl Eugen
Le nonidi 19 fructidor, an CCXXIV, Carl Eugen Hoyos a écrit : > This site claims that ISO disagrees: > http://stackoverflow.com/questions/5243012/is-it-guaranteed-to-be-safe-to-perform-memcpy0-0-0 > > (No opinion whatsoever here, just a ticket.) I stand corrected. Regards,
On Sun, Sep 04, 2016 at 09:15:47PM +0200, Carl Eugen Hoyos wrote: > Hi! > > Attached patch fixes ticket #5128. > > Please comment, Carl Eugen > avpacket.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > 0ddcbcddd2981c7ce86bf15943a1a4065a412b35 0001-lavc-avpacket-Fix-undefined-behaviour-do-not-pass-a-.patch > From a3dcd65c313e6b456fcb05915508d8d583c1840e Mon Sep 17 00:00:00 2001 > From: Carl Eugen Hoyos <cehoyos@ag.or.at> > Date: Sun, 4 Sep 2016 21:11:02 +0200 > Subject: [PATCH] lavc/avpacket: Fix undefined behaviour, do not pass a null > pointer to memcpy(). > > Fixes ticket #5128. > --- > libavcodec/avpacket.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) LGTM thx [...]
2016-09-04 22:43 GMT+02:00 Michael Niedermayer <michael@niedermayer.cc>: > On Sun, Sep 04, 2016 at 09:15:47PM +0200, Carl Eugen Hoyos wrote: >> Fixes ticket #5128. >> --- >> libavcodec/avpacket.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) > > LGTM Patch applied. Thank you, Carl Eugen
diff --git a/libavcodec/avpacket.c b/libavcodec/avpacket.c index 92186892..fa2844d 100644 --- a/libavcodec/avpacket.c +++ b/libavcodec/avpacket.c @@ -581,7 +581,8 @@ int av_packet_ref(AVPacket *dst, const AVPacket *src) ret = packet_alloc(&dst->buf, src->size); if (ret < 0) goto fail; - memcpy(dst->buf->data, src->data, src->size); + if (src->size) + memcpy(dst->buf->data, src->data, src->size); dst->data = dst->buf->data; } else {
Hi! Attached patch fixes ticket #5128. Please comment, Carl Eugen From a3dcd65c313e6b456fcb05915508d8d583c1840e Mon Sep 17 00:00:00 2001 From: Carl Eugen Hoyos <cehoyos@ag.or.at> Date: Sun, 4 Sep 2016 21:11:02 +0200 Subject: [PATCH] lavc/avpacket: Fix undefined behaviour, do not pass a null pointer to memcpy(). Fixes ticket #5128. --- libavcodec/avpacket.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)