[PATCH 01/13] vfs: verify param type in vfs_parse_sb_flag()
From: Miklos Szeredi <hidden>
Date: 2019-06-19 12:32:15
Also in:
linux-fsdevel, lkml
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
vfs_parse_sb_flag() accepted any kind of param with a matching key, not just a flag. This is wrong, only allow flag type and return -EINVAL otherwise. Signed-off-by: Miklos Szeredi <redacted> --- fs/fs_context.c | 31 +++++++++++++++---------------- 1 file changed, 15 insertions(+), 16 deletions(-)
diff --git a/fs/fs_context.c b/fs/fs_context.c
index 103643c68e3f..e56310fd8c75 100644
--- a/fs/fs_context.c
+++ b/fs/fs_context.c@@ -81,30 +81,29 @@ static const char *const forbidden_sb_flag[] = { /* * Check for a common mount option that manipulates s_flags. */ -static int vfs_parse_sb_flag(struct fs_context *fc, const char *key) +static int vfs_parse_sb_flag(struct fs_context *fc, struct fs_parameter *param) { - unsigned int token; + const char *key = param->key; + unsigned int set, clear; unsigned int i; for (i = 0; i < ARRAY_SIZE(forbidden_sb_flag); i++) if (strcmp(key, forbidden_sb_flag[i]) == 0) return -EINVAL; - token = lookup_constant(common_set_sb_flag, key, 0); - if (token) { - fc->sb_flags |= token; - fc->sb_flags_mask |= token; - return 0; - } + set = lookup_constant(common_set_sb_flag, key, 0); + clear = lookup_constant(common_clear_sb_flag, key, 0); + if (!set && !clear) + return -ENOPARAM; - token = lookup_constant(common_clear_sb_flag, key, 0); - if (token) { - fc->sb_flags &= ~token; - fc->sb_flags_mask |= token; - return 0; - } + if (param->type != fs_value_is_flag) + return invalf(fc, "%s: Unexpected value for '%s'", + fc->fs_type->name, param->key); - return -ENOPARAM; + fc->sb_flags |= set; + fc->sb_flags &= ~clear; + fc->sb_flags_mask |= set | clear; + return 0; } /**
@@ -130,7 +129,7 @@ int vfs_parse_fs_param(struct fs_context *fc, struct fs_parameter *param) if (!param->key) return invalf(fc, "Unnamed parameter\n"); - ret = vfs_parse_sb_flag(fc, param->key); + ret = vfs_parse_sb_flag(fc, param); if (ret != -ENOPARAM) return ret;
--
2.21.0