5.15-stable review patch. If anyone has any objections, please let me know.
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From: Roman Smirnov r.smirnov@omp.ru
[ Upstream commit 2510859475d7f46ed7940db0853f3342bf1b65ee ]
The echo_interval is not limited in any way during mounting, which makes it possible to write a large number to it. This can cause an overflow when multiplying ctx->echo_interval by HZ in match_server().
Add constraints for echo_interval to smb3_fs_context_parse_param().
Found by Linux Verification Center (linuxtesting.org) with Svace.
Fixes: adfeb3e00e8e1 ("cifs: Make echo interval tunable") Cc: stable@vger.kernel.org Signed-off-by: Roman Smirnov r.smirnov@omp.ru Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/cifs/fs_context.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/fs/cifs/fs_context.c b/fs/cifs/fs_context.c index 24c42043a2271..c3a71c69d3395 100644 --- a/fs/cifs/fs_context.c +++ b/fs/cifs/fs_context.c @@ -1088,6 +1088,11 @@ static int smb3_fs_context_parse_param(struct fs_context *fc, ctx->closetimeo = HZ * result.uint_32; break; case Opt_echo_interval: + if (result.uint_32 < SMB_ECHO_INTERVAL_MIN || + result.uint_32 > SMB_ECHO_INTERVAL_MAX) { + cifs_errorf(fc, "echo interval is out of bounds\n"); + goto cifs_parse_mount_err; + } ctx->echo_interval = result.uint_32; break; case Opt_snapshot: