| Message ID | 20181024110047.17274-1-peron.clem@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] mmc-utils: fix overlapping with strncpy | expand |
Hi Chris, Could you have a look at this patch ? Thanks, Clement On Wed, 24 Oct 2018 at 13:00, Clément Péron <peron.clem@gmail.com> wrote: > > GCC 8.2 warns about an overlapping using strncpy. > > Replace strncpy with a memmove to avoid this issue. > > In file included from /usr/include/string.h:494, > from lsmmc.c:46: > In function ‘strncpy’, > inlined from ‘read_file’ at lsmmc.c:356:3: > /usr/include/x86_64-linux-gnu/bits/string_fortified.h:106:10: error: ‘__builtin_strncpy’ accessing 4096 bytes at offsets 0 and 1 overlaps 4095 bytes at offset 1 [-Werror=restrict] > return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest)); > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > cc1: all warnings being treated as errors > make: *** [Makefile:36: lsmmc.o] Error 1 > > Signed-off-by: Clément Péron <peron.clem@gmail.com> > --- > > v2: > repost with Chris Ball > > lsmmc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/lsmmc.c b/lsmmc.c > index c4faa00..bcb854d 100644 > --- a/lsmmc.c > +++ b/lsmmc.c > @@ -353,7 +353,7 @@ char *read_file(char *name) > line[strlen(line) - 1] = '\0'; > > while (isspace(line[0])) > - strncpy(&line[0], &line[1], sizeof(line)); > + memmove(&line[0], &line[1], sizeof(line)-1); > > return strdup(line); > } > -- > 2.19.1 >
Around Mon 05 Nov 2018 17:13:43 +0100 or thereabout, Clément Péron wrote: Hello, > Could you have a look at this patch ? > > Thanks, > Clement > > On Wed, 24 Oct 2018 at 13:00, Clément Péron <peron.clem@gmail.com> wrote: >> >> GCC 8.2 warns about an overlapping using strncpy. >> >> Replace strncpy with a memmove to avoid this issue. >> >> In file included from /usr/include/string.h:494, >> from lsmmc.c:46: >> In function ‘strncpy’, >> inlined from ‘read_file’ at lsmmc.c:356:3: >> /usr/include/x86_64-linux-gnu/bits/string_fortified.h:106:10: error: ‘__builtin_strncpy’ accessing 4096 bytes at offsets 0 and 1 overlaps 4095 bytes at offset 1 [-Werror=restrict] >> return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest)); >> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> cc1: all warnings being treated as errors >> make: *** [Makefile:36: lsmmc.o] Error 1 >> >> Signed-off-by: Clément Péron <peron.clem@gmail.com> Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no> >> --- >> >> v2: >> repost with Chris Ball >> >> lsmmc.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/lsmmc.c b/lsmmc.c >> index c4faa00..bcb854d 100644 >> --- a/lsmmc.c >> +++ b/lsmmc.c >> @@ -353,7 +353,7 @@ char *read_file(char *name) >> line[strlen(line) - 1] = '\0'; >> >> while (isspace(line[0])) >> - strncpy(&line[0], &line[1], sizeof(line)); >> + memmove(&line[0], &line[1], sizeof(line)-1); >> >> return strdup(line); >> } >> -- >> 2.19.1 This works well for me at least.
Hi, Am Montag, 5. November 2018, 17:13:43 CET schrieben Sie: > Hi Chris, > > Could you have a look at this patch ? > > Thanks, > Clement > > On Wed, 24 Oct 2018 at 13:00, Clément Péron <peron.clem@gmail.com> wrote: > > GCC 8.2 warns about an overlapping using strncpy. > > > > Replace strncpy with a memmove to avoid this issue. while memmove does not suffer from this limitation, I don't see any reason to move the whole string at all - furthermore multiple times in worst case. Since we leave the function with a strdup() call, we could just pass an adjusted start pointer to strdup() without the need to move things before. I sent a patch "lsmmc: rework string trimming" which follows this approach. (Yes, sorry, I did not checked the ML before - so I didn't noticed your patches... ) Regards Michael > > > > In file included from /usr/include/string.h:494, > > > > from lsmmc.c:46: > > In function ‘strncpy’, > > > > inlined from ‘read_file’ at lsmmc.c:356:3: > > /usr/include/x86_64-linux-gnu/bits/string_fortified.h:106:10: error: > > ‘__builtin_strncpy’ accessing 4096 bytes at offsets 0 and 1 overlaps 4095 > > bytes at offset 1 [-Werror=restrict]> > > return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest)); > > > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > cc1: all warnings being treated as errors > > make: *** [Makefile:36: lsmmc.o] Error 1 > > > > Signed-off-by: Clément Péron <peron.clem@gmail.com> > > --- > > > > v2: > > repost with Chris Ball > > > > lsmmc.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/lsmmc.c b/lsmmc.c > > index c4faa00..bcb854d 100644 > > --- a/lsmmc.c > > +++ b/lsmmc.c > > @@ -353,7 +353,7 @@ char *read_file(char *name) > > > > line[strlen(line) - 1] = '\0'; > > > > while (isspace(line[0])) > > > > - strncpy(&line[0], &line[1], sizeof(line)); > > + memmove(&line[0], &line[1], sizeof(line)-1); > > > > return strdup(line); > > > > } > > > > -- > > 2.19.1
diff --git a/lsmmc.c b/lsmmc.c index c4faa00..bcb854d 100644 --- a/lsmmc.c +++ b/lsmmc.c @@ -353,7 +353,7 @@ char *read_file(char *name) line[strlen(line) - 1] = '\0'; while (isspace(line[0])) - strncpy(&line[0], &line[1], sizeof(line)); + memmove(&line[0], &line[1], sizeof(line)-1); return strdup(line); }
GCC 8.2 warns about an overlapping using strncpy. Replace strncpy with a memmove to avoid this issue. In file included from /usr/include/string.h:494, from lsmmc.c:46: In function ‘strncpy’, inlined from ‘read_file’ at lsmmc.c:356:3: /usr/include/x86_64-linux-gnu/bits/string_fortified.h:106:10: error: ‘__builtin_strncpy’ accessing 4096 bytes at offsets 0 and 1 overlaps 4095 bytes at offset 1 [-Werror=restrict] return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest)); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors make: *** [Makefile:36: lsmmc.o] Error 1 Signed-off-by: Clément Péron <peron.clem@gmail.com> --- v2: repost with Chris Ball lsmmc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)