From ff49bf1867578f23a5ffdd38f927f6e1e16796c4 Mon Sep 17 00:00:00 2001 From: Fedor Pchelkin Date: Wed, 6 Dec 2023 23:09:13 +0300 Subject: [PATCH] net: 9p: avoid freeing uninit memory in p9pdu_vreadf If some of p9pdu_readf() calls inside case 'T' in p9pdu_vreadf() fails, the error path is not handled properly. *wnames or members of *wnames array may be left uninitialized and invalidly freed. Initialize *wnames to NULL in beginning of case 'T'. Initialize the first *wnames array element to NULL and nullify the failing *wnames element so that the error path freeing loop stops on the first NULL element and doesn't proceed further. Found by Linux Verification Center (linuxtesting.org). Fixes: ace51c4dd2f9 ("9p: add new protocol support code") Signed-off-by: Fedor Pchelkin Message-ID: <20231206200913.16135-1-pchelkin@ispras.ru> Cc: stable@vger.kernel.org Reviewed-by: Simon Horman Reviewed-by: Christian Schoenebeck Signed-off-by: Dominique Martinet --- net/9p/protocol.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/net/9p/protocol.c b/net/9p/protocol.c index 4e3a2a1ffcb3..0e6603b1ec90 100644 --- a/net/9p/protocol.c +++ b/net/9p/protocol.c @@ -394,6 +394,8 @@ p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt, uint16_t *nwname = va_arg(ap, uint16_t *); char ***wnames = va_arg(ap, char ***); + *wnames = NULL; + errcode = p9pdu_readf(pdu, proto_version, "w", nwname); if (!errcode) { @@ -403,6 +405,8 @@ p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt, GFP_NOFS); if (!*wnames) errcode = -ENOMEM; + else + (*wnames)[0] = NULL; } if (!errcode) { @@ -414,8 +418,10 @@ p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt, proto_version, "s", &(*wnames)[i]); - if (errcode) + if (errcode) { + (*wnames)[i] = NULL; break; + } } } @@ -423,11 +429,14 @@ p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt, if (*wnames) { int i; - for (i = 0; i < *nwname; i++) + for (i = 0; i < *nwname; i++) { + if (!(*wnames)[i]) + break; kfree((*wnames)[i]); + } + kfree(*wnames); + *wnames = NULL; } - kfree(*wnames); - *wnames = NULL; } } break;