| Message ID | 20190412121626.19829-3-berrange@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | misc set of fixes for warnings under GCC 9 | expand |
On 12/04/2019 14:16, Daniel P. Berrangé wrote: > In file included from /usr/include/string.h:494, > from include/qemu/osdep.h:101, > from linux-user/elfload.c:2: > In function ‘strncpy’, > inlined from ‘fill_psinfo’ at linux-user/elfload.c:3208:12, > inlined from ‘fill_note_info’ at linux-user/elfload.c:3390:5, > inlined from ‘elf_core_dump’ at linux-user/elfload.c:3539:9: > /usr/include/bits/string_fortified.h:106:10: warning: ‘__builtin_strncpy’ specified bound 16 equals destination size [-Wstringop-truncation] > 106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest)); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > We don't require the field to be NUL terminated, so can just > copy the lower of the string length and the target field size > using memcpy. > > Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> > --- > linux-user/elfload.c | 10 ++++------ > 1 file changed, 4 insertions(+), 6 deletions(-) > > diff --git a/linux-user/elfload.c b/linux-user/elfload.c > index c1a26021f8..caa060f7b7 100644 > --- a/linux-user/elfload.c > +++ b/linux-user/elfload.c > @@ -3180,6 +3180,7 @@ static int fill_psinfo(struct target_elf_prpsinfo *psinfo, const TaskState *ts) > { > char *base_filename; > unsigned int i, len; > + size_t pathlen; > > (void) memset(psinfo, 0, sizeof (*psinfo)); > > @@ -3201,12 +3202,9 @@ static int fill_psinfo(struct target_elf_prpsinfo *psinfo, const TaskState *ts) > psinfo->pr_gid = getgid(); > > base_filename = g_path_get_basename(ts->bprm->filename); > - /* > - * Using strncpy here is fine: at max-length, > - * this field is not NUL-terminated. > - */ Keep and update the comment, it explains why we don't need to add the NUL at the end when MIN() is sizeof(psinfo->pr_fname). > - (void) strncpy(psinfo->pr_fname, base_filename, > - sizeof(psinfo->pr_fname)); > + pathlen = strlen(base_filename) + 1; > + pathlen = MIN(pathlen, sizeof(psinfo->pr_fname)); > + memcpy(psinfo->pr_fname, base_filename, pathlen); > > g_free(base_filename); > bswap_psinfo(psinfo); > Thanks, Laurent
diff --git a/linux-user/elfload.c b/linux-user/elfload.c index c1a26021f8..caa060f7b7 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -3180,6 +3180,7 @@ static int fill_psinfo(struct target_elf_prpsinfo *psinfo, const TaskState *ts) { char *base_filename; unsigned int i, len; + size_t pathlen; (void) memset(psinfo, 0, sizeof (*psinfo)); @@ -3201,12 +3202,9 @@ static int fill_psinfo(struct target_elf_prpsinfo *psinfo, const TaskState *ts) psinfo->pr_gid = getgid(); base_filename = g_path_get_basename(ts->bprm->filename); - /* - * Using strncpy here is fine: at max-length, - * this field is not NUL-terminated. - */ - (void) strncpy(psinfo->pr_fname, base_filename, - sizeof(psinfo->pr_fname)); + pathlen = strlen(base_filename) + 1; + pathlen = MIN(pathlen, sizeof(psinfo->pr_fname)); + memcpy(psinfo->pr_fname, base_filename, pathlen); g_free(base_filename); bswap_psinfo(psinfo);
In file included from /usr/include/string.h:494, from include/qemu/osdep.h:101, from linux-user/elfload.c:2: In function ‘strncpy’, inlined from ‘fill_psinfo’ at linux-user/elfload.c:3208:12, inlined from ‘fill_note_info’ at linux-user/elfload.c:3390:5, inlined from ‘elf_core_dump’ at linux-user/elfload.c:3539:9: /usr/include/bits/string_fortified.h:106:10: warning: ‘__builtin_strncpy’ specified bound 16 equals destination size [-Wstringop-truncation] 106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We don't require the field to be NUL terminated, so can just copy the lower of the string length and the target field size using memcpy. Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> --- linux-user/elfload.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-)