| From 11e1cffb7e2492ddac4ab8d19ce466783adbb957 Mon Sep 17 00:00:00 2001 |
| From: Darren Kenny <darren.kenny@oracle.com> |
| Date: Tue, 29 Mar 2022 10:49:56 +0000 |
| Subject: [PATCH 36/38] fs/btrfs: Fix several fuzz issues with invalid dir item |
| sizing |
| |
| According to the btrfs code in Linux, the structure of a directory item |
| leaf should be of the form: |
| |
| |struct btrfs_dir_item|name|data| |
| |
| in GRUB the name len and data len are in the grub_btrfs_dir_item |
| structure's n and m fields respectively. |
| |
| The combined size of the structure, name and data should be less than |
| the allocated memory, a difference to the Linux kernel's struct |
| btrfs_dir_item is that the grub_btrfs_dir_item has an extra field for |
| where the name is stored, so we adjust for that too. |
| |
| Signed-off-by: Darren Kenny <darren.kenny@oracle.com> |
| Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> |
| --- |
| grub-core/fs/btrfs.c | 26 ++++++++++++++++++++++++++ |
| 1 file changed, 26 insertions(+) |
| |
| diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c |
| index 937153306..139c6616d 100644 |
| --- a/grub-core/fs/btrfs.c |
| +++ b/grub-core/fs/btrfs.c |
| @@ -1991,6 +1991,7 @@ grub_btrfs_dir (grub_device_t device, const char *path, |
| int r = 0; |
| grub_uint64_t tree; |
| grub_uint8_t type; |
| + grub_size_t est_size = 0; |
| |
| if (!data) |
| return grub_errno; |
| @@ -2049,6 +2050,18 @@ grub_btrfs_dir (grub_device_t device, const char *path, |
| break; |
| } |
| |
| + if (direl == NULL || |
| + grub_add (grub_le_to_cpu16 (direl->n), |
| + grub_le_to_cpu16 (direl->m), &est_size) || |
| + grub_add (est_size, sizeof (*direl), &est_size) || |
| + grub_sub (est_size, sizeof (direl->name), &est_size) || |
| + est_size > allocated) |
| + { |
| + grub_errno = GRUB_ERR_OUT_OF_RANGE; |
| + r = -grub_errno; |
| + goto out; |
| + } |
| + |
| for (cdirel = direl; |
| (grub_uint8_t *) cdirel - (grub_uint8_t *) direl |
| < (grub_ssize_t) elemsize; |
| @@ -2059,6 +2072,19 @@ grub_btrfs_dir (grub_device_t device, const char *path, |
| char c; |
| struct grub_btrfs_inode inode; |
| struct grub_dirhook_info info; |
| + |
| + if (cdirel == NULL || |
| + grub_add (grub_le_to_cpu16 (cdirel->n), |
| + grub_le_to_cpu16 (cdirel->m), &est_size) || |
| + grub_add (est_size, sizeof (*cdirel), &est_size) || |
| + grub_sub (est_size, sizeof (cdirel->name), &est_size) || |
| + est_size > allocated) |
| + { |
| + grub_errno = GRUB_ERR_OUT_OF_RANGE; |
| + r = -grub_errno; |
| + goto out; |
| + } |
| + |
| err = grub_btrfs_read_inode (data, &inode, cdirel->key.object_id, |
| tree); |
| grub_memset (&info, 0, sizeof (info)); |
| -- |
| 2.37.0.rc0.104.g0611611a94-goog |
| |