Messages in this thread Patch in this message | | | From | Jim Meyering <> | Subject | [PATCH] Btrfs: avoid buffer overrun in btrfs_printk | Date | Thu, 26 Apr 2012 18:35:12 +0200 |
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The buffer read-overrun would be triggered by a printk format starting with <N>, where N is a single digit. NUL-terminate after strncpy. Use memcpy, not strncpy, since we know the string we're copying fits in the destination buffer and contains no NUL byte.
Signed-off-by: Jim Meyering <meyering@redhat.com> --- fs/btrfs/super.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 5ddf172..626f574 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -180,23 +180,24 @@ const char *logtypes[] = { void btrfs_printk(struct btrfs_fs_info *fs_info, const char *fmt, ...) { struct super_block *sb = fs_info->sb; char lvl[4]; struct va_format vaf; va_list args; const char *type = logtypes[4];
va_start(args, fmt);
if (fmt[0] == '<' && isdigit(fmt[1]) && fmt[2] == '>') { - strncpy(lvl, fmt, 3); + memcpy(lvl, fmt, 3); + lvl[3] = '\0'; fmt += 3; type = logtypes[fmt[1] - '0']; } else *lvl = '\0';
vaf.fmt = fmt; vaf.va = &args; printk("%sBTRFS %s (device %s): %pV", lvl, type, sb->s_id, &vaf); }
/* -- 1.7.10.336.gc5e31
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