CVE - CVE-2021-47375

CVE-ID
CVE-2021-47375	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
In the Linux kernel, the following vulnerability has been resolved: blktrace: Fix uaf in blk_trace access after removing by sysfs There is an use-after-free problem triggered by following process: P1(sda) P2(sdb) echo 0 > /sys/block/sdb/trace/enable blk_trace_remove_queue synchronize_rcu blk_trace_free relay_close rcu_read_lock __blk_add_trace trace_note_tsk (Iterate running_trace_list) relay_close_buf relay_destroy_buf kfree(buf) trace_note(sdb's bt) relay_reserve buf->offset <- nullptr deference (use-after-free) !!! rcu_read_unlock [ 502.714379] BUG: kernel NULL pointer dereference, address: 0000000000000010 [ 502.715260] #PF: supervisor read access in kernel mode [ 502.715903] #PF: error_code(0x0000) - not-present page [ 502.716546] PGD 103984067 P4D 103984067 PUD 17592b067 PMD 0 [ 502.717252] Oops: 0000 [#1] SMP [ 502.720308] RIP: 0010:trace_note.isra.0+0x86/0x360 [ 502.732872] Call Trace: [ 502.733193] __blk_add_trace.cold+0x137/0x1a3 [ 502.733734] blk_add_trace_rq+0x7b/0xd0 [ 502.734207] blk_add_trace_rq_issue+0x54/0xa0 [ 502.734755] blk_mq_start_request+0xde/0x1b0 [ 502.735287] scsi_queue_rq+0x528/0x1140 ... [ 502.742704] sg_new_write.isra.0+0x16e/0x3e0 [ 502.747501] sg_ioctl+0x466/0x1100 Reproduce method: ioctl(/dev/sda, BLKTRACESETUP, blk_user_trace_setup[buf_size=127]) ioctl(/dev/sda, BLKTRACESTART) ioctl(/dev/sdb, BLKTRACESETUP, blk_user_trace_setup[buf_size=127]) ioctl(/dev/sdb, BLKTRACESTART) echo 0 > /sys/block/sdb/trace/enable & // Add delay(mdelay/msleep) before kernel enters blk_trace_free() ioctl$SG_IO(/dev/sda, SG_IO, ...) // Enters trace_note_tsk() after blk_trace_free() returned // Use mdelay in rcu region rather than msleep(which may schedule out) Remove blk_trace from running_list before calling blk_trace_free() by sysfs if blk_trace is at Blktrace_running state.
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://git.kernel.org/stable/c/3815fe7371d2411ce164281cef40d9fc7b323dee URL:https://git.kernel.org/stable/c/3815fe7371d2411ce164281cef40d9fc7b323dee MISC:https://git.kernel.org/stable/c/488da313edf3abea7f7733efe011c96b23740ab5 URL:https://git.kernel.org/stable/c/488da313edf3abea7f7733efe011c96b23740ab5 MISC:https://git.kernel.org/stable/c/5afedf670caf30a2b5a52da96eb7eac7dee6a9c9 URL:https://git.kernel.org/stable/c/5afedf670caf30a2b5a52da96eb7eac7dee6a9c9 MISC:https://git.kernel.org/stable/c/677e362ba807f3aafe6f405c07e0b37244da5222 URL:https://git.kernel.org/stable/c/677e362ba807f3aafe6f405c07e0b37244da5222 MISC:https://git.kernel.org/stable/c/a5f8e86192612d0183047448d8bbe7918b3f1a26 URL:https://git.kernel.org/stable/c/a5f8e86192612d0183047448d8bbe7918b3f1a26 MISC:https://git.kernel.org/stable/c/d56171d9360c0170c5c5f8f7e2362a2e999eca40 URL:https://git.kernel.org/stable/c/d56171d9360c0170c5c5f8f7e2362a2e999eca40 MISC:https://git.kernel.org/stable/c/dacfd5e4d1142bfb3809aab3634a375f6f373269 URL:https://git.kernel.org/stable/c/dacfd5e4d1142bfb3809aab3634a375f6f373269 MISC:https://git.kernel.org/stable/c/ebb8d26d93c3ec3c7576c52a8373a2309423c069 URL:https://git.kernel.org/stable/c/ebb8d26d93c3ec3c7576c52a8373a2309423c069
Assigning CNA
kernel.org
Date Record Created
20240521	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20240521)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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