From 66081a72517a131430dcf986775f3268aafcb546 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Sat, 29 Sep 2012 22:23:19 +0200 Subject: [PATCH] sysfs: sysfs_pathname/sysfs_add_one: Use strlcat() instead of strcat() The warning check for duplicate sysfs entries can cause a buffer overflow when printing the warning, as strcat() doesn't check buffer sizes. Use strlcat() instead. Since strlcat() doesn't return a pointer to the passed buffer, unlike strcat(), I had to convert the nested concatenation in sysfs_add_one() to an admittedly more obscure comma operator construct, to avoid emitting code for the concatenation if CONFIG_BUG is disabled. Signed-off-by: Geert Uytterhoeven Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/dir.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index 6b0bb00d4d2b..2fbdff6be25c 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -485,20 +485,18 @@ int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) /** * sysfs_pathname - return full path to sysfs dirent * @sd: sysfs_dirent whose path we want - * @path: caller allocated buffer + * @path: caller allocated buffer of size PATH_MAX * * Gives the name "/" to the sysfs_root entry; any path returned * is relative to wherever sysfs is mounted. - * - * XXX: does no error checking on @path size */ static char *sysfs_pathname(struct sysfs_dirent *sd, char *path) { if (sd->s_parent) { sysfs_pathname(sd->s_parent, path); - strcat(path, "/"); + strlcat(path, "/", PATH_MAX); } - strcat(path, sd->s_name); + strlcat(path, sd->s_name, PATH_MAX); return path; } @@ -531,9 +529,11 @@ int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) char *path = kzalloc(PATH_MAX, GFP_KERNEL); WARN(1, KERN_WARNING "sysfs: cannot create duplicate filename '%s'\n", - (path == NULL) ? sd->s_name : - strcat(strcat(sysfs_pathname(acxt->parent_sd, path), "/"), - sd->s_name)); + (path == NULL) ? sd->s_name + : (sysfs_pathname(acxt->parent_sd, path), + strlcat(path, "/", PATH_MAX), + strlcat(path, sd->s_name, PATH_MAX), + path)); kfree(path); } -- 2.20.1