File 0039-linux-user-avoid-string-truncation-.patch of Package qemu

Overview Repositories Revisions Requests Users Attributes Meta

File 0039-linux-user-avoid-string-truncation-.patch of Package qemu (Revision 0c48b99a6b4c4233ee85619bf51fc72c)

Currently displaying revision 0c48b99a6b4c4233ee85619bf51fc72c , Show latest

From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= <berrange@redhat.com>
Date: Wed, 1 May 2019 15:46:46 +0100
Subject: linux-user: avoid string truncation warnings in uname field copying
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

In file included from /usr/include/string.h:494,
                 from include/qemu/osdep.h:101,
                 from linux-user/uname.c:20:
In function ‘strncpy’,
    inlined from ‘sys_uname’ at linux-user/uname.c:94:3:
/usr/include/bits/string_fortified.h:106:10: warning: ‘__builtin_strncpy’ 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>
[BR: Played with indent to avoid error from checkpatch.pl]
(cherry picked from commit b2acfb55962bc8caeaa50a5158da2f701f2c1f7c)
Signed-off-by: Bruce Rogers <brogers@suse.com>
---
 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..0c6ddf2ad9 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)

Places

File 0039-linux-user-avoid-string-truncation-.patch of Package qemu (Revision 0c48b99a6b4c4233ee85619bf51fc72c)

Places