From b2acfb55962bc8caeaa50a5158da2f701f2c1f7c Mon Sep 17 00:00:00 2001
From: =?utf8?q?Daniel=20P=2E=20Berrang=C3=A9?= <berrange@redhat.com>
Date: Wed, 1 May 2019 15:46:46 +0100
Subject: [PATCH] linux-user: avoid string truncation warnings in uname field
copying
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In file included from /usr/include/string.h:494,
from include/qemu/osdep.h:101,
from linux-user/uname.c:20:
In function âstrncpyâ,
inlined from âsys_unameâ at linux-user/uname.c:94:3:
/usr/include/bits/string_fortified.h:106:10: warning: â__builtin_strncpyâ output may be truncated copying 64 bytes from a string of length 64 [-Wstringop-truncation]
106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We don't care where the NUL terminator in the original uname
field was. It suffices to copy the entire original field and
simply force a NUL terminator at the end of the new field.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20190501144646.4851-1-berrange@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
linux-user/uname.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/linux-user/uname.c b/linux-user/uname.c
index 313b79dbad..1c05f95387 100644
--- a/linux-user/uname.c
+++ b/linux-user/uname.c
@@ -72,9 +72,8 @@ const char *cpu_to_uname_machine(void *cpu_env)
#define COPY_UTSNAME_FIELD(dest, src) \
do { \
- /* __NEW_UTS_LEN doesn't include terminating null */ \
- (void) strncpy((dest), (src), __NEW_UTS_LEN); \
- (dest)[__NEW_UTS_LEN] = '\0'; \
+ memcpy((dest), (src), MIN(sizeof(src), sizeof(dest))); \
+ (dest)[sizeof(dest) - 1] = '\0'; \
} while (0)
int sys_uname(struct new_utsname *buf)
--
2.30.2