From 7eff3453cbd7e0bfc7524d59694119b5ca844778 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Fri, 5 Jul 2024 09:15:08 +0800 Subject: [PATCH 1/3] ovl: pass string to ovl_parse_layer() So it can be used for parsing the Opt_lowerdir. Signed-off-by: Zhihao Cheng Link: https://lore.kernel.org/r/20240705011510.794025-2-chengzhihao1@huawei.com Signed-off-by: Christian Brauner --- fs/overlayfs/params.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/fs/overlayfs/params.c b/fs/overlayfs/params.c index 4860fcc4611bb..52e3860973b7e 100644 --- a/fs/overlayfs/params.c +++ b/fs/overlayfs/params.c @@ -365,10 +365,9 @@ static void ovl_add_layer(struct fs_context *fc, enum ovl_opt layer, } } -static int ovl_parse_layer(struct fs_context *fc, struct fs_parameter *param, - enum ovl_opt layer) +static int ovl_parse_layer(struct fs_context *fc, const char *layer_name, enum ovl_opt layer) { - char *name = kstrdup(param->string, GFP_KERNEL); + char *name = kstrdup(layer_name, GFP_KERNEL); bool upper = (layer == Opt_upperdir || layer == Opt_workdir); struct path path; int err; @@ -582,7 +581,7 @@ static int ovl_parse_param(struct fs_context *fc, struct fs_parameter *param) case Opt_datadir_add: case Opt_upperdir: case Opt_workdir: - err = ovl_parse_layer(fc, param, opt); + err = ovl_parse_layer(fc, param->string, opt); break; case Opt_default_permissions: config->default_permissions = true; From ca76ac36bb6068866feca185045e7edf2a8f392f Mon Sep 17 00:00:00 2001 From: Zhihao Cheng Date: Fri, 5 Jul 2024 09:15:09 +0800 Subject: [PATCH 2/3] ovl: fix wrong lowerdir number check for parameter Opt_lowerdir The max count of lowerdir is OVL_MAX_STACK[500], which is broken by commit 37f32f526438("ovl: fix memory leak in ovl_parse_param()") for parameter Opt_lowerdir. Since commit 819829f0319a("ovl: refactor layer parsing helpers") and commit 24e16e385f22("ovl: add support for appending lowerdirs one by one") added check ovl_mount_dir_check() in function ovl_parse_param_lowerdir(), the 'ctx->nr' should be smaller than OVL_MAX_STACK, after commit 37f32f526438("ovl: fix memory leak in ovl_parse_param()") is applied, the 'ctx->nr' is updated before the check ovl_mount_dir_check(), which leads the max count of lowerdir to become 499 for parameter Opt_lowerdir. Fix it by replacing lower layers parsing code with the existing helper function ovl_parse_layer(). Fixes: 37f32f526438 ("ovl: fix memory leak in ovl_parse_param()") Signed-off-by: Zhihao Cheng Link: https://lore.kernel.org/r/20240705011510.794025-3-chengzhihao1@huawei.com Reviewed-by: Amir Goldstein Signed-off-by: Christian Brauner --- fs/overlayfs/params.c | 40 +++++++--------------------------------- 1 file changed, 7 insertions(+), 33 deletions(-) diff --git a/fs/overlayfs/params.c b/fs/overlayfs/params.c index 52e3860973b7e..8dd834c7f291c 100644 --- a/fs/overlayfs/params.c +++ b/fs/overlayfs/params.c @@ -353,6 +353,8 @@ static void ovl_add_layer(struct fs_context *fc, enum ovl_opt layer, case Opt_datadir_add: ctx->nr_data++; fallthrough; + case Opt_lowerdir: + fallthrough; case Opt_lowerdir_add: WARN_ON(ctx->nr >= ctx->capacity); l = &ctx->lower[ctx->nr++]; @@ -375,7 +377,7 @@ static int ovl_parse_layer(struct fs_context *fc, const char *layer_name, enum o if (!name) return -ENOMEM; - if (upper) + if (upper || layer == Opt_lowerdir) err = ovl_mount_dir(name, &path); else err = ovl_mount_dir_noesc(name, &path); @@ -431,7 +433,6 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc) { int err; struct ovl_fs_context *ctx = fc->fs_private; - struct ovl_fs_context_layer *l; char *dup = NULL, *iter; ssize_t nr_lower, nr; bool data_layer = false; @@ -471,35 +472,11 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc) goto out_err; } - if (nr_lower > ctx->capacity) { - err = -ENOMEM; - l = krealloc_array(ctx->lower, nr_lower, sizeof(*ctx->lower), - GFP_KERNEL_ACCOUNT); - if (!l) - goto out_err; - - ctx->lower = l; - ctx->capacity = nr_lower; - } - iter = dup; - l = ctx->lower; - for (nr = 0; nr < nr_lower; nr++, l++) { - ctx->nr++; - memset(l, 0, sizeof(*l)); - - err = ovl_mount_dir(iter, &l->path); + for (nr = 0; nr < nr_lower; nr++) { + err = ovl_parse_layer(fc, iter, Opt_lowerdir); if (err) - goto out_put; - - err = ovl_mount_dir_check(fc, &l->path, Opt_lowerdir, iter, false); - if (err) - goto out_put; - - err = -ENOMEM; - l->name = kstrdup(iter, GFP_KERNEL_ACCOUNT); - if (!l->name) - goto out_put; + goto out_err; if (data_layer) ctx->nr_data++; @@ -517,7 +494,7 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc) */ if (ctx->nr_data > 0) { pr_err("regular lower layers cannot follow data lower layers"); - goto out_put; + goto out_err; } data_layer = false; @@ -531,9 +508,6 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc) kfree(dup); return 0; -out_put: - ovl_reset_lowerdirs(ctx); - out_err: kfree(dup); From 441e36ef5b347d9ab4f54f7b54853266be687556 Mon Sep 17 00:00:00 2001 From: Zhihao Cheng Date: Fri, 5 Jul 2024 09:15:10 +0800 Subject: [PATCH 3/3] ovl: ovl_parse_param_lowerdir: Add missed '\n' for pr_err Add '\n' for pr_err in function ovl_parse_param_lowerdir(), which ensures that error message is displayed at once. Fixes: b36a5780cb44 ("ovl: modify layer parameter parsing") Signed-off-by: Zhihao Cheng Link: https://lore.kernel.org/r/20240705011510.794025-4-chengzhihao1@huawei.com Signed-off-by: Christian Brauner --- fs/overlayfs/params.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/overlayfs/params.c b/fs/overlayfs/params.c index 8dd834c7f291c..d0568c0913412 100644 --- a/fs/overlayfs/params.c +++ b/fs/overlayfs/params.c @@ -449,7 +449,7 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc) return 0; if (*name == ':') { - pr_err("cannot append lower layer"); + pr_err("cannot append lower layer\n"); return -EINVAL; } @@ -493,7 +493,7 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc) * there are no data layers. */ if (ctx->nr_data > 0) { - pr_err("regular lower layers cannot follow data lower layers"); + pr_err("regular lower layers cannot follow data lower layers\n"); goto out_err; }