| 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-2022-49648: tracing/histograms: Fix memory leak problem |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| tracing/histograms: Fix memory leak problem |
| |
| This reverts commit 46bbe5c671e06f070428b9be142cc4ee5cedebac. |
| |
| As commit 46bbe5c671e0 ("tracing: fix double free") said, the |
| "double free" problem reported by clang static analyzer is: |
| > In parse_var_defs() if there is a problem allocating |
| > var_defs.expr, the earlier var_defs.name is freed. |
| > This free is duplicated by free_var_defs() which frees |
| > the rest of the list. |
| |
| However, if there is a problem allocating N-th var_defs.expr: |
| + in parse_var_defs(), the freed 'earlier var_defs.name' is |
| actually the N-th var_defs.name; |
| + then in free_var_defs(), the names from 0th to (N-1)-th are freed; |
| |
| IF ALLOCATING PROBLEM HAPPENED HERE!!! -+ |
| \ |
| | |
| 0th 1th (N-1)-th N-th V |
| +-------------+-------------+-----+-------------+----------- |
| var_defs: | name | expr | name | expr | ... | name | expr | name | /// |
| +-------------+-------------+-----+-------------+----------- |
| |
| These two frees don't act on same name, so there was no "double free" |
| problem before. Conversely, after that commit, we get a "memory leak" |
| problem because the above "N-th var_defs.name" is not freed. |
| |
| If enable CONFIG_DEBUG_KMEMLEAK and inject a fault at where the N-th |
| var_defs.expr allocated, then execute on shell like: |
| $ echo 'hist:key=call_site:val=$v1,$v2:v1=bytes_req,v2=bytes_alloc' > \ |
| /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger |
| |
| Then kmemleak reports: |
| unreferenced object 0xffff8fb100ef3518 (size 8): |
| comm "bash", pid 196, jiffies 4295681690 (age 28.538s) |
| hex dump (first 8 bytes): |
| 76 31 00 00 b1 8f ff ff v1...... |
| backtrace: |
| [<0000000038fe4895>] kstrdup+0x2d/0x60 |
| [<00000000c99c049a>] event_hist_trigger_parse+0x206f/0x20e0 |
| [<00000000ae70d2cc>] trigger_process_regex+0xc0/0x110 |
| [<0000000066737a4c>] event_trigger_write+0x75/0xd0 |
| [<000000007341e40c>] vfs_write+0xbb/0x2a0 |
| [<0000000087fde4c2>] ksys_write+0x59/0xd0 |
| [<00000000581e9cdf>] do_syscall_64+0x3a/0x80 |
| [<00000000cf3b065c>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 |
| |
| The Linux kernel CVE team has assigned CVE-2022-49648 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 4.19.149 with commit 240dd5118a9e0454f280ffeae63f22bd14735733 and fixed in 4.19.253 with commit eb622d5580b9e2ff694f62da6410618bd73853cb |
| Issue introduced in 5.4.69 with commit e92c490f104993cea35e5f5d5108ac12df1850ac and fixed in 5.4.207 with commit ecc6dec12c33aa92c086cd702af9f544ddaf3c75 |
| Issue introduced in 5.9 with commit 46bbe5c671e06f070428b9be142cc4ee5cedebac and fixed in 5.10.132 with commit 78a1400c42ee11197eb1f0f85ba51df9a4fdfff0 |
| Issue introduced in 5.9 with commit 46bbe5c671e06f070428b9be142cc4ee5cedebac and fixed in 5.15.56 with commit 22eeff55679d9e7c0f768c79bfbd83e2f8142d89 |
| Issue introduced in 5.9 with commit 46bbe5c671e06f070428b9be142cc4ee5cedebac and fixed in 5.18.13 with commit 4d453eb5e1eec89971aa5b3262857ee26cfdffd3 |
| Issue introduced in 5.9 with commit 46bbe5c671e06f070428b9be142cc4ee5cedebac and fixed in 5.19 with commit 7edc3945bdce9c39198a10d6129377a5c53559c2 |
| Issue introduced in 5.8.13 with commit e3a23511638a3dcf0275c1e71a46d1ca2e2e6788 |
| |
| 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-2022-49648 |
| 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: |
| kernel/trace/trace_events_hist.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/eb622d5580b9e2ff694f62da6410618bd73853cb |
| https://git.kernel.org/stable/c/ecc6dec12c33aa92c086cd702af9f544ddaf3c75 |
| https://git.kernel.org/stable/c/78a1400c42ee11197eb1f0f85ba51df9a4fdfff0 |
| https://git.kernel.org/stable/c/22eeff55679d9e7c0f768c79bfbd83e2f8142d89 |
| https://git.kernel.org/stable/c/4d453eb5e1eec89971aa5b3262857ee26cfdffd3 |
| https://git.kernel.org/stable/c/7edc3945bdce9c39198a10d6129377a5c53559c2 |
