From: Fedor Tokarev <ftokarev@gmail.com>
Date: Sat, 28 Mar 2020 14:56:55 +0300
Subject: [PATCH] net: sunrpc: Fix off-by-one issues in 'rpc_ntop6'
Git-commit: 118917d696dc59fd3e1741012c2f9db2294bed6f
Patch-mainline: v5.8
References: git-fixes
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 <ftokarev@gmail.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Acked-by: NeilBrown <neilb@suse.com>
---
net/sunrpc/addr.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/net/sunrpc/addr.c
+++ b/net/sunrpc/addr.c
@@ -81,11 +81,11 @@ static size_t rpc_ntop6(const struct soc
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);