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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 ‘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>
This commit is contained in:
Daniel P. Berrangé 2019-05-01 15:46:46 +01:00 committed by Laurent Vivier
parent d7eb2b928a
commit b2acfb5596
1 changed files with 2 additions and 3 deletions
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5
linux-user/uname.c
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@ -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)