| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2021-47585: btrfs: fix memory leak in __add_inode_ref() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| btrfs: fix memory leak in __add_inode_ref() |
| |
| Line 1169 (#3) allocates a memory chunk for victim_name by kmalloc(), |
| but when the function returns in line 1184 (#4) victim_name allocated |
| by line 1169 (#3) is not freed, which will lead to a memory leak. |
| There is a similar snippet of code in this function as allocating a memory |
| chunk for victim_name in line 1104 (#1) as well as releasing the memory |
| in line 1116 (#2). |
| |
| We should kfree() victim_name when the return value of backref_in_log() |
| is less than zero and before the function returns in line 1184 (#4). |
| |
| 1057 static inline int __add_inode_ref(struct btrfs_trans_handle *trans, |
| 1058 struct btrfs_root *root, |
| 1059 struct btrfs_path *path, |
| 1060 struct btrfs_root *log_root, |
| 1061 struct btrfs_inode *dir, |
| 1062 struct btrfs_inode *inode, |
| 1063 u64 inode_objectid, u64 parent_objectid, |
| 1064 u64 ref_index, char *name, int namelen, |
| 1065 int *search_done) |
| 1066 { |
| |
| 1104 victim_name = kmalloc(victim_name_len, GFP_NOFS); |
| // #1: kmalloc (victim_name-1) |
| 1105 if (!victim_name) |
| 1106 return -ENOMEM; |
| |
| 1112 ret = backref_in_log(log_root, &search_key, |
| 1113 parent_objectid, victim_name, |
| 1114 victim_name_len); |
| 1115 if (ret < 0) { |
| 1116 kfree(victim_name); // #2: kfree (victim_name-1) |
| 1117 return ret; |
| 1118 } else if (!ret) { |
| |
| 1169 victim_name = kmalloc(victim_name_len, GFP_NOFS); |
| // #3: kmalloc (victim_name-2) |
| 1170 if (!victim_name) |
| 1171 return -ENOMEM; |
| |
| 1180 ret = backref_in_log(log_root, &search_key, |
| 1181 parent_objectid, victim_name, |
| 1182 victim_name_len); |
| 1183 if (ret < 0) { |
| 1184 return ret; // #4: missing kfree (victim_name-2) |
| 1185 } else if (!ret) { |
| |
| 1241 return 0; |
| 1242 } |
| |
| The Linux kernel CVE team has assigned CVE-2021-47585 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.5 with commit d3316c8233bb05e0dd855d30aac347bb8ad76ee4 and fixed in 5.10.88 with commit 005d9292b5b2e71a009f911bd85d755009b37242 |
| Issue introduced in 5.5 with commit d3316c8233bb05e0dd855d30aac347bb8ad76ee4 and fixed in 5.15.11 with commit 493ff661d434d6bdf02e3a21adae04d7a0b4265d |
| Issue introduced in 5.5 with commit d3316c8233bb05e0dd855d30aac347bb8ad76ee4 and fixed in 5.16 with commit f35838a6930296fc1988764cfa54cb3f705c0665 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2021-47585 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| fs/btrfs/tree-log.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/005d9292b5b2e71a009f911bd85d755009b37242 |
| https://git.kernel.org/stable/c/493ff661d434d6bdf02e3a21adae04d7a0b4265d |
| https://git.kernel.org/stable/c/f35838a6930296fc1988764cfa54cb3f705c0665 |
