DEBIAN-CVE-2024-53166

In the Linux kernel, the following vulnerability has been resolved: block, bfq: fix bfqq uaf in bfqlimitdepth() Set new allocated bfqq to bic or remove freed bfqq from bic are both protected by bfqd->lock, however bfqlimitdepth() is deferencing bfqq from bic without the lock, this can lead to UAF if the iocontext is shared by multiple tasks. For example, test bfq with iouring can trigger following UAF in v6.6: ================================================================== BUG: KASAN: slab-use-after-free in bfqqgroup+0x15/0x50 Call Trace: <TASK> dumpstacklvl+0x47/0x80 printaddressdescription.constprop.0+0x66/0x300 printreport+0x3e/0x70 kasanreport+0xb4/0xf0 bfqqgroup+0x15/0x50 bfqqrequestoverlimit+0x130/0x9a0 bfqlimitdepth+0x1b5/0x480 _blkmqallocrequests+0x2b5/0xa00 blkmqgetnewrequests+0x11d/0x1d0 blkmqsubmitbio+0x286/0xb00 submitbionoacctnocheck+0x331/0x400 _blockwritefullfolio+0x3d0/0x640 writepagecb+0x3b/0xc0 writecachepages+0x254/0x6c0 writecachepages+0x254/0x6c0 dowritepages+0x192/0x310 filemapfdatawritewbc+0x95/0xc0 _filemapfdatawriterange+0x99/0xd0 filemapwriteandwaitrange.part.0+0x4d/0xa0 blkdevreaditer+0xef/0x1e0 ioread+0x1b6/0x8a0 ioissuesqe+0x87/0x300 iowqsubmitwork+0xeb/0x390 ioworkerhandlework+0x24d/0x550 iowqworker+0x27f/0x6c0 retfromforkasm+0x1b/0x30 </TASK> Allocated by task 808602: kasansavestack+0x1e/0x40 kasansettrack+0x21/0x30 _kasanslaballoc+0x83/0x90 kmemcacheallocnode+0x1b1/0x6d0 bfqgetqueue+0x138/0xfa0 bfqgetbfqqhandlesplit+0xe3/0x2c0 bfqinitrq+0x196/0xbb0 bfqinsertrequest.isra.0+0xb5/0x480 bfqinsertrequests+0x156/0x180 blkmqinsertrequest+0x15d/0x440 blkmqsubmitbio+0x8a4/0xb00 submitbionoacctnocheck+0x331/0x400 _blkdevdirectIOasync+0x2dd/0x330 blkdevwriteiter+0x39a/0x450 iowrite+0x22a/0x840 ioissuesqe+0x87/0x300 iowqsubmitwork+0xeb/0x390 ioworkerhandlework+0x24d/0x550 iowqworker+0x27f/0x6c0 retfromfork+0x2d/0x50 retfromforkasm+0x1b/0x30 Freed by task 808589: kasansavestack+0x1e/0x40 kasansettrack+0x21/0x30 kasansavefreeinfo+0x27/0x40 _kasanslabfree+0x126/0x1b0 kmemcachefree+0x10c/0x750 bfqputqueue+0x2dd/0x770 _bfqinsertrequest.isra.0+0x155/0x7a0 bfqinsertrequest.isra.0+0x122/0x480 bfqinsertrequests+0x156/0x180 blkmqdispatchpluglist+0x528/0x7e0 blkmqflushpluglist.part.0+0xe5/0x590 _blkflushplug+0x3b/0x90 blkfinishplug+0x40/0x60 dowritepages+0x19d/0x310 filemapfdatawritewbc+0x95/0xc0 _filemapfdatawriterange+0x99/0xd0 filemapwriteandwaitrange.part.0+0x4d/0xa0 blkdevreaditer+0xef/0x1e0 ioread+0x1b6/0x8a0 ioissuesqe+0x87/0x300 iowqsubmitwork+0xeb/0x390 ioworkerhandlework+0x24d/0x550 iowqworker+0x27f/0x6c0 retfromfork+0x2d/0x50 retfromforkasm+0x1b/0x30 Fix the problem by protecting bicto_bfqq() with bfqd->lock.