4.19-stable review patch. If anyone has any objections, please let me know.
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From: Fedor Pchelkin pchelkin@ispras.ru
commit ff49bf1867578f23a5ffdd38f927f6e1e16796c4 upstream.
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 pchelkin@ispras.ru Message-ID: 20231206200913.16135-1-pchelkin@ispras.ru Cc: stable@vger.kernel.org Reviewed-by: Simon Horman horms@kernel.org Reviewed-by: Christian Schoenebeck linux_oss@crudebyte.com Signed-off-by: Dominique Martinet asmadeus@codewreck.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/9p/protocol.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-)
--- a/net/9p/protocol.c +++ b/net/9p/protocol.c @@ -243,6 +243,8 @@ p9pdu_vreadf(struct p9_fcall *pdu, int p 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) { @@ -252,6 +254,8 @@ p9pdu_vreadf(struct p9_fcall *pdu, int p GFP_NOFS); if (!*wnames) errcode = -ENOMEM; + else + (*wnames)[0] = NULL; }
if (!errcode) { @@ -263,8 +267,10 @@ p9pdu_vreadf(struct p9_fcall *pdu, int p proto_version, "s", &(*wnames)[i]); - if (errcode) + if (errcode) { + (*wnames)[i] = NULL; break; + } } }
@@ -272,11 +278,14 @@ p9pdu_vreadf(struct p9_fcall *pdu, int p 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;