[PATCH AUTOSEL 4.19 126/172] net: sunrpc: Fix off-by-one issues in 'rpc_ntop6'
From: Sasha Levin <sashal@kernel.org>
Date: 2020-06-18 01:58:04
Also in:
linux-nfs, lkml, netdev
Subsystem:
kernel nfsd, sunrpc, and lockd servers, networking [general], nfs, sunrpc, and lockd clients, the rest · Maintainers:
Chuck Lever, Jeff Layton, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Trond Myklebust, Anna Schumaker, Linus Torvalds
From: Fedor Tokarev <redacted> [ Upstream commit 118917d696dc59fd3e1741012c2f9db2294bed6f ] Fix off-by-one issues in 'rpc_ntop6': - 'snprintf' returns the number of characters which would have been written if enough space had been available, excluding the terminating null byte. Thus, a return value of 'sizeof(scopebuf)' means that the last character was dropped. - 'strcat' adds a terminating null byte to the string, thus if len == buflen, the null byte is written past the end of the buffer. Signed-off-by: Fedor Tokarev <redacted> Signed-off-by: Anna Schumaker <redacted> Signed-off-by: Sasha Levin <sashal@kernel.org> --- net/sunrpc/addr.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/sunrpc/addr.c b/net/sunrpc/addr.c
index 2e0a6f92e563..8391c2785550 100644
--- a/net/sunrpc/addr.c
+++ b/net/sunrpc/addr.c@@ -81,11 +81,11 @@ static size_t rpc_ntop6(const struct sockaddr *sap, rc = snprintf(scopebuf, sizeof(scopebuf), "%c%u", IPV6_SCOPE_DELIMITER, sin6->sin6_scope_id); - if (unlikely((size_t)rc > sizeof(scopebuf))) + if (unlikely((size_t)rc >= sizeof(scopebuf))) return 0; len += rc; - if (unlikely(len > buflen)) + if (unlikely(len >= buflen)) return 0; strcat(buf, scopebuf);
--
2.25.1