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author | Amir Goldstein <amir73il@gmail.com> | 2023-10-11 17:07:03 +0300 |
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committer | Amir Goldstein <amir73il@gmail.com> | 2023-10-14 09:24:11 +0300 |
commit | 32db510708507f6133f496ff385cbd841d8f9098 (patch) | |
tree | 11f002bc14bc735248a64ef174756f3ddf4f3c07 /fs | |
parent | c34706acf40b43dd31f67c92c5a95d39666a1eb3 (diff) | |
download | linux-stable-32db510708507f6133f496ff385cbd841d8f9098.tar.gz linux-stable-32db510708507f6133f496ff385cbd841d8f9098.tar.bz2 linux-stable-32db510708507f6133f496ff385cbd841d8f9098.zip |
ovl: fix regression in showing lowerdir mount option
Before commit b36a5780cb44 ("ovl: modify layer parameter parsing"),
spaces and commas in lowerdir mount option value used to be escaped using
seq_show_option().
In current upstream, when lowerdir value has a space, it is not escaped
in /proc/mounts, e.g.:
none /mnt overlay rw,relatime,lowerdir=l l,upperdir=u,workdir=w 0 0
which results in broken output of the mount utility:
none on /mnt type overlay (rw,relatime,lowerdir=l)
Store the original lowerdir mount options before unescaping and show
them using the same escaping used for seq_show_option() in addition to
escaping the colon separator character.
Fixes: b36a5780cb44 ("ovl: modify layer parameter parsing")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/overlayfs/params.c | 38 |
1 files changed, 23 insertions, 15 deletions
diff --git a/fs/overlayfs/params.c b/fs/overlayfs/params.c index 17c74ef4f089..8b6bae320e8a 100644 --- a/fs/overlayfs/params.c +++ b/fs/overlayfs/params.c @@ -192,7 +192,8 @@ static ssize_t ovl_parse_param_split_lowerdirs(char *str) for (s = d = str;; s++, d++) { if (*s == '\\') { - s++; + /* keep esc chars in split lowerdir */ + *d++ = *s++; } else if (*s == ':') { bool next_colon = (*(s + 1) == ':'); @@ -267,7 +268,7 @@ static void ovl_unescape(char *s) } } -static int ovl_mount_dir(const char *name, struct path *path) +static int ovl_mount_dir(const char *name, struct path *path, bool upper) { int err = -ENOMEM; char *tmp = kstrdup(name, GFP_KERNEL); @@ -276,7 +277,7 @@ static int ovl_mount_dir(const char *name, struct path *path) ovl_unescape(tmp); err = ovl_mount_dir_noesc(tmp, path); - if (!err && path->dentry->d_flags & DCACHE_OP_REAL) { + if (!err && upper && path->dentry->d_flags & DCACHE_OP_REAL) { pr_err("filesystem on '%s' not supported as upperdir\n", tmp); path_put_init(path); @@ -297,7 +298,7 @@ static int ovl_parse_param_upperdir(const char *name, struct fs_context *fc, struct path path; char *dup; - err = ovl_mount_dir(name, &path); + err = ovl_mount_dir(name, &path, true); if (err) return err; @@ -500,7 +501,7 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc) l = &ctx->lower[nr]; memset(l, 0, sizeof(*l)); - err = ovl_mount_dir_noesc(dup_iter, &l->path); + err = ovl_mount_dir(dup_iter, &l->path, false); if (err) goto out_put; @@ -979,16 +980,23 @@ int ovl_show_options(struct seq_file *m, struct dentry *dentry) struct super_block *sb = dentry->d_sb; struct ovl_fs *ofs = OVL_FS(sb); size_t nr, nr_merged_lower = ofs->numlayer - ofs->numdatalayer; - char **lowerdatadirs = &ofs->config.lowerdirs[nr_merged_lower]; - - /* lowerdirs[] starts from offset 1 */ - seq_printf(m, ",lowerdir=%s", ofs->config.lowerdirs[1]); - /* dump regular lower layers */ - for (nr = 2; nr < nr_merged_lower; nr++) - seq_printf(m, ":%s", ofs->config.lowerdirs[nr]); - /* dump data lower layers */ - for (nr = 0; nr < ofs->numdatalayer; nr++) - seq_printf(m, "::%s", lowerdatadirs[nr]); + + /* + * lowerdirs[] starts from offset 1, then + * >= 0 regular lower layers prefixed with : and + * >= 0 data-only lower layers prefixed with :: + * + * we need to escase comma and space like seq_show_option() does and + * we also need to escape the colon separator from lowerdir paths. + */ + seq_puts(m, ",lowerdir="); + for (nr = 1; nr < ofs->numlayer; nr++) { + if (nr > 1) + seq_putc(m, ':'); + if (nr >= nr_merged_lower) + seq_putc(m, ':'); + seq_escape(m, ofs->config.lowerdirs[nr], ":, \t\n\\"); + } if (ofs->config.upperdir) { seq_show_option(m, "upperdir", ofs->config.upperdir); seq_show_option(m, "workdir", ofs->config.workdir); |