| Message ID | 20231205080524.6635-1-pchelkin@ispras.ru (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net: 9p: avoid freeing uninit memory in p9pdu_vreadf | expand |
Fedor Pchelkin wrote on Tue, Dec 05, 2023 at 11:05:22AM +0300: > If an error occurs while processing an array of strings in p9pdu_vreadf > then uninitialized members of *wnames array are freed. > > Fix this by iterating over only lower indices of the array. > > Found by Linux Verification Center (linuxtesting.org). You might want to mark that as Reported-by: somehow instead of a free form comment > > Fixes: ace51c4dd2f9 ("9p: add new protocol support code") > Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru> That aside, it looks good to me -- good find! I'll push this to Linus with the other pending fix we have next week > --- > net/9p/protocol.c | 7 ++----- > 1 file changed, 2 insertions(+), 5 deletions(-) > > diff --git a/net/9p/protocol.c b/net/9p/protocol.c > index 4e3a2a1ffcb3..d33387e74a66 100644 > --- a/net/9p/protocol.c > +++ b/net/9p/protocol.c > @@ -393,6 +393,7 @@ p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt, > case 'T':{ > uint16_t *nwname = va_arg(ap, uint16_t *); > char ***wnames = va_arg(ap, char ***); > + int i; > > errcode = p9pdu_readf(pdu, proto_version, > "w", nwname); > @@ -406,8 +407,6 @@ p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt, > } > > if (!errcode) { > - int i; > - > for (i = 0; i < *nwname; i++) { > errcode = > p9pdu_readf(pdu, > @@ -421,9 +420,7 @@ p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt, > > if (errcode) { > if (*wnames) { > - int i; > - > - for (i = 0; i < *nwname; i++) > + while (--i >= 0) > kfree((*wnames)[i]); > } > kfree(*wnames);
diff --git a/net/9p/protocol.c b/net/9p/protocol.c index 4e3a2a1ffcb3..d33387e74a66 100644 --- a/net/9p/protocol.c +++ b/net/9p/protocol.c @@ -393,6 +393,7 @@ p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt, case 'T':{ uint16_t *nwname = va_arg(ap, uint16_t *); char ***wnames = va_arg(ap, char ***); + int i; errcode = p9pdu_readf(pdu, proto_version, "w", nwname); @@ -406,8 +407,6 @@ p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt, } if (!errcode) { - int i; - for (i = 0; i < *nwname; i++) { errcode = p9pdu_readf(pdu, @@ -421,9 +420,7 @@ p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt, if (errcode) { if (*wnames) { - int i; - - for (i = 0; i < *nwname; i++) + while (--i >= 0) kfree((*wnames)[i]); } kfree(*wnames);
If an error occurs while processing an array of strings in p9pdu_vreadf then uninitialized members of *wnames array are freed. Fix this by iterating over only lower indices of the array. Found by Linux Verification Center (linuxtesting.org). Fixes: ace51c4dd2f9 ("9p: add new protocol support code") Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru> --- net/9p/protocol.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-)