Messages in this thread | | | Subject | Re: [PATCH] f2fs: Replace strncpy with memcpy | From | Chao Yu <> | Date | Mon, 2 Jul 2018 09:53:28 +0800 |
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On 2018/7/2 4:57, Guenter Roeck wrote: > gcc 8.1.0 complains: > > fs/f2fs/namei.c: In function 'f2fs_update_extension_list': > fs/f2fs/namei.c:257:3: warning: > 'strncpy' output truncated before terminating nul copying > as many bytes from a string as its length > fs/f2fs/namei.c:249:3: warning: > 'strncpy' output truncated before terminating nul copying > as many bytes from a string as its length > > Using strncpy() is indeed less than perfect since the length of data to > be copied has already been determined with strlen(). Replace strncpy() > with memcpy() to address the warning and optimize the code a little. > > Signed-off-by: Guenter Roeck <linux@roeck-us.net> > --- > fs/f2fs/namei.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c > index 231b7f3ea7d3..e75607544f7c 100644 > --- a/fs/f2fs/namei.c > +++ b/fs/f2fs/namei.c > @@ -246,7 +246,7 @@ int f2fs_update_extension_list(struct f2fs_sb_info *sbi, const char *name, > return -EINVAL; > > if (hot) { > - strncpy(extlist[count], name, strlen(name)); > + memcpy(extlist[count], name, strlen(name));
How about replacing with strcpy(extlist[count], name)? Because name length has already been checked before f2fs_update_extension_list, it should be valid, and will not cause overflow during copying.
Thanks,
> sbi->raw_super->hot_ext_count = hot_count + 1; > } else { > char buf[F2FS_MAX_EXTENSION][F2FS_EXTENSION_LEN]; > @@ -254,7 +254,7 @@ int f2fs_update_extension_list(struct f2fs_sb_info *sbi, const char *name, > memcpy(buf, &extlist[cold_count], > F2FS_EXTENSION_LEN * hot_count); > memset(extlist[cold_count], 0, F2FS_EXTENSION_LEN); > - strncpy(extlist[cold_count], name, strlen(name)); > + memcpy(extlist[cold_count], name, strlen(name)); > memcpy(&extlist[cold_count + 1], buf, > F2FS_EXTENSION_LEN * hot_count); > sbi->raw_super->extension_count = cpu_to_le32(cold_count + 1); >
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