Bug 1224804 (CVE-2024-35784) - VUL-0: CVE-2024-35784: kernel: btrfs: fix deadlock with fiemap and extent locking
Summary: VUL-0: CVE-2024-35784: kernel: btrfs: fix deadlock with fiemap and extent loc...
Status: NEW
Alias: CVE-2024-35784
Product: SUSE Security Incidents
Classification: Novell Products
Component: Incidents (show other bugs)
Version: unspecified
Hardware: Other Other
: P3 - Medium : Normal
Target Milestone: ---
Assignee: Filipe Manana
QA Contact: Security Team bot
URL: https://smash.suse.de/issue/406363/
Whiteboard: CVSSv3.1:SUSE:CVE-2024-35784:5.5:(AV:...
Keywords:
Depends on:
Blocks:
 
Reported: 2024-05-21 12:31 UTC by SMASH SMASH
Modified: 2024-07-08 14:59 UTC (History)
3 users (show)

See Also:
Found By: Security Response Team
Services Priority:
Business Priority:
Blocker: ---
Marketing QA Status: ---
IT Deployment: ---

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Description SMASH SMASH 2024-05-21 12:31:20 UTC 
In the Linux kernel, the following vulnerability has been resolved:

btrfs: fix deadlock with fiemap and extent locking

While working on the patchset to remove extent locking I got a lockdep
splat with fiemap and pagefaulting with my new extent lock replacement
lock.

This deadlock exists with our normal code, we just don't have lockdep
annotations with the extent locking so we've never noticed it.

Since we're copying the fiemap extent to user space on every iteration
we have the chance of pagefaulting.  Because we hold the extent lock for
the entire range we could mkwrite into a range in the file that we have
mmap'ed.  This would deadlock with the following stack trace

[<0>] lock_extent+0x28d/0x2f0
[<0>] btrfs_page_mkwrite+0x273/0x8a0
[<0>] do_page_mkwrite+0x50/0xb0
[<0>] do_fault+0xc1/0x7b0
[<0>] __handle_mm_fault+0x2fa/0x460
[<0>] handle_mm_fault+0xa4/0x330
[<0>] do_user_addr_fault+0x1f4/0x800
[<0>] exc_page_fault+0x7c/0x1e0
[<0>] asm_exc_page_fault+0x26/0x30
[<0>] rep_movs_alternative+0x33/0x70
[<0>] _copy_to_user+0x49/0x70
[<0>] fiemap_fill_next_extent+0xc8/0x120
[<0>] emit_fiemap_extent+0x4d/0xa0
[<0>] extent_fiemap+0x7f8/0xad0
[<0>] btrfs_fiemap+0x49/0x80
[<0>] __x64_sys_ioctl+0x3e1/0xb50
[<0>] do_syscall_64+0x94/0x1a0
[<0>] entry_SYSCALL_64_after_hwframe+0x6e/0x76

I wrote an fstest to reproduce this deadlock without my replacement lock
and verified that the deadlock exists with our existing locking.

To fix this simply don't take the extent lock for the entire duration of
the fiemap.  This is safe in general because we keep track of where we
are when we're searching the tree, so if an ordered extent updates in
the middle of our fiemap call we'll still emit the correct extents
because we know what offset we were on before.

The only place we maintain the lock is searching delalloc.  Since the
delalloc stuff can change during writeback we want to lock the extent
range so we have a consistent view of delalloc at the time we're
checking to see if we need to set the delalloc flag.

With this patch applied we no longer deadlock with my testcase.

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2024-35784
https://www.cve.org/CVERecord?id=CVE-2024-35784
https://git.kernel.org/stable/c/89bca7fe6382d61e88c67a0b0e7bce315986fb8b
https://git.kernel.org/stable/c/b0ad381fa7690244802aed119b478b4bdafc31dd
https://git.kernel.org/stable/c/ded566b4637f1b6b4c9ba74e7d0b8493e93f19cf
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2024/CVE-2024-35784.mbox
https://bugzilla.redhat.com/show_bug.cgi?id=2281067
Comment 1 Joey Lee 2024-05-21 17:24:59 UTC 
https://www.suse.com/security/cve/CVE-2024-35784.html
cvss 5.5
Comment 13 Maintenance Automation 2024-06-21 12:32:03 UTC 
SUSE-SU-2024:2135-1: An update that solves 428 vulnerabilities, contains 15 features and has 78 security fixes can now be installed.

Category: security (important)
Bug References: 1012628, 1065729, 1181674, 1187716, 1193599, 1194869, 1207948, 1208593, 1209657, 1213573, 1214852, 1215199, 1216196, 1216358, 1216702, 1217169, 1217384, 1217408, 1217489, 1217750, 1217959, 1218205, 1218336, 1218447, 1218562, 1218779, 1218917, 1219104, 1219170, 1219596, 1219623, 1219834, 1220021, 1220045, 1220120, 1220148, 1220328, 1220342, 1220428, 1220430, 1220569, 1220587, 1220738, 1220783, 1220915, 1221044, 1221276, 1221293, 1221303, 1221375, 1221504, 1221612, 1221615, 1221635, 1221645, 1221649, 1221765, 1221777, 1221783, 1221816, 1221829, 1221830, 1221858, 1222115, 1222173, 1222264, 1222273, 1222294, 1222301, 1222303, 1222304, 1222307, 1222357, 1222366, 1222368, 1222371, 1222378, 1222379, 1222385, 1222422, 1222426, 1222428, 1222437, 1222445, 1222459, 1222464, 1222489, 1222522, 1222525, 1222527, 1222531, 1222532, 1222549, 1222550, 1222557, 1222559, 1222563, 1222585, 1222586, 1222596, 1222606, 1222608, 1222613, 1222615, 1222618, 1222622, 1222624, 1222627, 1222630, 1222635, 1222721, 1222727, 1222769, 1222771, 1222772, 1222775, 1222777, 1222780, 1222782, 1222793, 1222799, 1222801, 1222968, 1223007, 1223011, 1223015, 1223016, 1223020, 1223023, 1223024, 1223030, 1223033, 1223034, 1223035, 1223038, 1223039, 1223041, 1223045, 1223046, 1223051, 1223052, 1223058, 1223060, 1223061, 1223076, 1223077, 1223084, 1223111, 1223113, 1223138, 1223143, 1223187, 1223189, 1223190, 1223191, 1223198, 1223202, 1223285, 1223315, 1223338, 1223369, 1223380, 1223384, 1223390, 1223439, 1223462, 1223532, 1223539, 1223575, 1223590, 1223591, 1223592, 1223593, 1223625, 1223628, 1223629, 1223633, 1223634, 1223637, 1223641, 1223643, 1223649, 1223650, 1223651, 1223652, 1223653, 1223654, 1223655, 1223660, 1223661, 1223663, 1223664, 1223665, 1223666, 1223668, 1223669, 1223670, 1223671, 1223675, 1223677, 1223678, 1223686, 1223692, 1223693, 1223695, 1223696, 1223698, 1223705, 1223712, 1223718, 1223728, 1223732, 1223735, 1223739, 1223741, 1223744, 1223745, 1223747, 1223748, 1223749, 1223750, 1223752, 1223754, 1223757, 1223759, 1223761, 1223762, 1223774, 1223782, 1223787, 1223788, 1223789, 1223790, 1223802, 1223805, 1223810, 1223822, 1223827, 1223831, 1223834, 1223838, 1223869, 1223870, 1223871, 1223872, 1223874, 1223944, 1223945, 1223946, 1223991, 1224076, 1224096, 1224098, 1224099, 1224137, 1224166, 1224174, 1224177, 1224180, 1224181, 1224331, 1224348, 1224423, 1224429, 1224430, 1224432, 1224433, 1224437, 1224438, 1224442, 1224443, 1224445, 1224449, 1224477, 1224479, 1224480, 1224481, 1224482, 1224486, 1224487, 1224488, 1224491, 1224492, 1224493, 1224494, 1224495, 1224500, 1224501, 1224502, 1224504, 1224505, 1224506, 1224507, 1224508, 1224509, 1224511, 1224513, 1224517, 1224519, 1224521, 1224524, 1224525, 1224526, 1224530, 1224531, 1224534, 1224537, 1224541, 1224542, 1224543, 1224546, 1224550, 1224552, 1224553, 1224555, 1224557, 1224558, 1224559, 1224562, 1224565, 1224566, 1224567, 1224568, 1224569, 1224571, 1224573, 1224576, 1224577, 1224578, 1224579, 1224580, 1224581, 1224582, 1224585, 1224586, 1224587, 1224588, 1224592, 1224596, 1224598, 1224600, 1224601, 1224602, 1224603, 1224605, 1224607, 1224608, 1224609, 1224611, 1224613, 1224615, 1224617, 1224618, 1224620, 1224621, 1224622, 1224623, 1224624, 1224626, 1224627, 1224628, 1224629, 1224630, 1224632, 1224633, 1224634, 1224636, 1224637, 1224638, 1224639, 1224640, 1224643, 1224644, 1224645, 1224646, 1224647, 1224648, 1224649, 1224650, 1224651, 1224652, 1224653, 1224654, 1224657, 1224660, 1224663, 1224664, 1224665, 1224666, 1224667, 1224668, 1224671, 1224672, 1224674, 1224675, 1224676, 1224677, 1224678, 1224679, 1224680, 1224681, 1224682, 1224683, 1224685, 1224686, 1224687, 1224688, 1224692, 1224696, 1224697, 1224699, 1224701, 1224703, 1224704, 1224705, 1224706, 1224707, 1224709, 1224710, 1224712, 1224714, 1224716, 1224717, 1224718, 1224719, 1224720, 1224721, 1224722, 1224723, 1224725, 1224727, 1224728, 1224729, 1224730, 1224731, 1224732, 1224733, 1224736, 1224738, 1224739, 1224740, 1224741, 1224742, 1224747, 1224749, 1224763, 1224764, 1224765, 1224766, 1224790, 1224792, 1224793, 1224803, 1224804, 1224866, 1224936, 1224989, 1225007, 1225053, 1225133, 1225134, 1225136, 1225172, 1225502, 1225578, 1225579, 1225580, 1225593, 1225605, 1225607, 1225610, 1225616, 1225618, 1225640, 1225642, 1225692, 1225694, 1225695, 1225696, 1225698, 1225699, 1225704, 1225705, 1225708, 1225710, 1225712, 1225714, 1225715, 1225720, 1225722, 1225728, 1225734, 1225735, 1225736, 1225747, 1225748, 1225749, 1225750, 1225756, 1225765, 1225766, 1225769, 1225773, 1225775, 1225842, 1225945
CVE References: CVE-2023-0160, CVE-2023-47233, CVE-2023-52434, CVE-2023-52458, CVE-2023-52463, CVE-2023-52472, CVE-2023-52483, CVE-2023-52492, CVE-2023-52503, CVE-2023-52591, CVE-2023-52608, CVE-2023-52616, CVE-2023-52618, CVE-2023-52631, CVE-2023-52635, CVE-2023-52640, CVE-2023-52641, CVE-2023-52645, CVE-2023-52652, CVE-2023-52653, CVE-2023-52654, CVE-2023-52655, CVE-2023-52657, CVE-2023-52658, CVE-2023-52659, CVE-2023-52660, CVE-2023-52661, CVE-2023-52662, CVE-2023-52663, CVE-2023-52664, CVE-2023-52667, CVE-2023-52669, CVE-2023-52670, CVE-2023-52671, CVE-2023-52673, CVE-2023-52674, CVE-2023-52675, CVE-2023-52676, CVE-2023-52678, CVE-2023-52679, CVE-2023-52680, CVE-2023-52681, CVE-2023-52683, CVE-2023-52685, CVE-2023-52686, CVE-2023-52687, CVE-2023-52690, CVE-2023-52691, CVE-2023-52692, CVE-2023-52693, CVE-2023-52694, CVE-2023-52695, CVE-2023-52696, CVE-2023-52697, CVE-2023-52698, CVE-2023-52771, CVE-2023-52772, CVE-2023-52860, CVE-2023-52882, CVE-2023-6238, CVE-2023-6270, CVE-2023-6531, CVE-2023-7042, CVE-2024-0639, CVE-2024-21823, CVE-2024-22099, CVE-2024-23848, CVE-2024-24861, CVE-2024-25739, CVE-2024-26601, CVE-2024-26611, CVE-2024-26614, CVE-2024-26632, CVE-2024-26638, CVE-2024-26642, CVE-2024-26643, CVE-2024-26652, CVE-2024-26654, CVE-2024-26656, CVE-2024-26657, CVE-2024-26671, CVE-2024-26673, CVE-2024-26674, CVE-2024-26675, CVE-2024-26679, CVE-2024-26684, CVE-2024-26685, CVE-2024-26692, CVE-2024-26696, CVE-2024-26697, CVE-2024-26704, CVE-2024-26714, CVE-2024-26726, CVE-2024-26731, CVE-2024-26733, CVE-2024-26736, CVE-2024-26737, CVE-2024-26739, CVE-2024-26740, CVE-2024-26742, CVE-2024-26756, CVE-2024-26757, CVE-2024-26760, CVE-2024-267600, CVE-2024-26761, CVE-2024-26764, CVE-2024-26769, CVE-2024-26772, CVE-2024-26773, CVE-2024-26774, CVE-2024-26775, CVE-2024-26779, CVE-2024-26783, CVE-2024-26786, CVE-2024-26791, CVE-2024-26793, CVE-2024-26794, CVE-2024-26802, CVE-2024-26805, CVE-2024-26807, CVE-2024-26815, CVE-2024-26816, CVE-2024-26822, CVE-2024-26828, CVE-2024-26832, CVE-2024-26836, CVE-2024-26844, CVE-2024-26846, CVE-2024-26848, CVE-2024-26853, CVE-2024-26854, CVE-2024-26855, CVE-2024-26856, CVE-2024-26857, CVE-2024-26858, CVE-2024-26860, CVE-2024-26861, CVE-2024-26862, CVE-2024-26866, CVE-2024-26868, CVE-2024-26870, CVE-2024-26878, CVE-2024-26881, CVE-2024-26882, CVE-2024-26883, CVE-2024-26884, CVE-2024-26885, CVE-2024-26898, CVE-2024-26899, CVE-2024-26900, CVE-2024-26901, CVE-2024-26903, CVE-2024-26906, CVE-2024-26909, CVE-2024-26921, CVE-2024-26922, CVE-2024-26923, CVE-2024-26925, CVE-2024-26928, CVE-2024-26932, CVE-2024-26933, CVE-2024-26934, CVE-2024-26935, CVE-2024-26937, CVE-2024-26938, CVE-2024-26940, CVE-2024-26943, CVE-2024-26945, CVE-2024-26946, CVE-2024-26948, CVE-2024-26949, CVE-2024-26950, CVE-2024-26951, CVE-2024-26956, CVE-2024-26957, CVE-2024-26958, CVE-2024-26960, CVE-2024-26961, CVE-2024-26962, CVE-2024-26963, CVE-2024-26964, CVE-2024-26972, CVE-2024-26973, CVE-2024-26978, CVE-2024-26979, CVE-2024-26981, CVE-2024-26982, CVE-2024-26983, CVE-2024-26984, CVE-2024-26986, CVE-2024-26988, CVE-2024-26989, CVE-2024-26990, CVE-2024-26991, CVE-2024-26992, CVE-2024-26993, CVE-2024-26994, CVE-2024-26995, CVE-2024-26996, CVE-2024-26997, CVE-2024-26999, CVE-2024-27000, CVE-2024-27001, CVE-2024-27002, CVE-2024-27003, CVE-2024-27004, CVE-2024-27008, CVE-2024-27013, CVE-2024-27014, CVE-2024-27022, CVE-2024-27027, CVE-2024-27028, CVE-2024-27029, CVE-2024-27030, CVE-2024-27031, CVE-2024-27036, CVE-2024-27046, CVE-2024-27056, CVE-2024-27057, CVE-2024-27062, CVE-2024-27067, CVE-2024-27080, CVE-2024-27388, CVE-2024-27389, CVE-2024-27393, CVE-2024-27395, CVE-2024-27396, CVE-2024-27398, CVE-2024-27399, CVE-2024-27400, CVE-2024-27401, CVE-2024-27405, CVE-2024-27408, CVE-2024-27410, CVE-2024-27411, CVE-2024-27412, CVE-2024-27413, CVE-2024-27416, CVE-2024-27417, CVE-2024-27418, CVE-2024-27431, CVE-2024-27432, CVE-2024-27434, CVE-2024-27435, CVE-2024-27436, CVE-2024-35784, CVE-2024-35786, CVE-2024-35788, CVE-2024-35789, CVE-2024-35790, CVE-2024-35791, CVE-2024-35794, CVE-2024-35795, CVE-2024-35796, CVE-2024-35799, CVE-2024-35800, CVE-2024-35801, CVE-2024-35803, CVE-2024-35804, CVE-2024-35806, CVE-2024-35808, CVE-2024-35809, CVE-2024-35810, CVE-2024-35811, CVE-2024-35812, CVE-2024-35813, CVE-2024-35814, CVE-2024-35815, CVE-2024-35817, CVE-2024-35819, CVE-2024-35821, CVE-2024-35822, CVE-2024-35823, CVE-2024-35824, CVE-2024-35825, CVE-2024-35828, CVE-2024-35829, CVE-2024-35830, CVE-2024-35833, CVE-2024-35834, CVE-2024-35835, CVE-2024-35836, CVE-2024-35837, CVE-2024-35838, CVE-2024-35841, CVE-2024-35842, CVE-2024-35845, CVE-2024-35847, CVE-2024-35849, CVE-2024-35850, CVE-2024-35851, CVE-2024-35852, CVE-2024-35854, CVE-2024-35860, CVE-2024-35861, CVE-2024-35862, CVE-2024-35863, CVE-2024-35864, CVE-2024-35865, CVE-2024-35866, CVE-2024-35867, CVE-2024-35868, CVE-2024-35869, CVE-2024-35870, CVE-2024-35872, CVE-2024-35875, CVE-2024-35877, CVE-2024-35878, CVE-2024-35879, CVE-2024-35883, CVE-2024-35885, CVE-2024-35887, CVE-2024-35889, CVE-2024-35891, CVE-2024-35895, CVE-2024-35901, CVE-2024-35903, CVE-2024-35904, CVE-2024-35905, CVE-2024-35907, CVE-2024-35909, CVE-2024-35911, CVE-2024-35912, CVE-2024-35914, CVE-2024-35915, CVE-2024-35916, CVE-2024-35917, CVE-2024-35921, CVE-2024-35922, CVE-2024-35924, CVE-2024-35927, CVE-2024-35928, CVE-2024-35930, CVE-2024-35931, CVE-2024-35932, CVE-2024-35933, CVE-2024-35935, CVE-2024-35936, CVE-2024-35937, CVE-2024-35938, CVE-2024-35940, CVE-2024-35943, CVE-2024-35944, CVE-2024-35945, CVE-2024-35946, CVE-2024-35947, CVE-2024-35950, CVE-2024-35951, CVE-2024-35952, CVE-2024-35953, CVE-2024-35954, CVE-2024-35955, CVE-2024-35956, CVE-2024-35958, CVE-2024-35959, CVE-2024-35960, CVE-2024-35961, CVE-2024-35963, CVE-2024-35964, CVE-2024-35965, CVE-2024-35966, CVE-2024-35967, CVE-2024-35969, CVE-2024-35971, CVE-2024-35972, CVE-2024-35973, CVE-2024-35974, CVE-2024-35975, CVE-2024-35977, CVE-2024-35978, CVE-2024-35981, CVE-2024-35982, CVE-2024-35984, CVE-2024-35986, CVE-2024-35989, CVE-2024-35990, CVE-2024-35991, CVE-2024-35992, CVE-2024-35995, CVE-2024-35997, CVE-2024-35999, CVE-2024-36002, CVE-2024-36006, CVE-2024-36007, CVE-2024-36009, CVE-2024-36011, CVE-2024-36012, CVE-2024-36013, CVE-2024-36014, CVE-2024-36015, CVE-2024-36016, CVE-2024-36018, CVE-2024-36019, CVE-2024-36020, CVE-2024-36021, CVE-2024-36025, CVE-2024-36026, CVE-2024-36029, CVE-2024-36030, CVE-2024-36032, CVE-2024-36880, CVE-2024-36885, CVE-2024-36890, CVE-2024-36891, CVE-2024-36893, CVE-2024-36894, CVE-2024-36895, CVE-2024-36896, CVE-2024-36897, CVE-2024-36898, CVE-2024-36906, CVE-2024-36918, CVE-2024-36921, CVE-2024-36922, CVE-2024-36928, CVE-2024-36930, CVE-2024-36931, CVE-2024-36936, CVE-2024-36940, CVE-2024-36941, CVE-2024-36942, CVE-2024-36944, CVE-2024-36947, CVE-2024-36949, CVE-2024-36950, CVE-2024-36951, CVE-2024-36955, CVE-2024-36959
Jira References: PED-3184, PED-3311, PED-3535, PED-4486, PED-4593, PED-5062, PED-542, PED-5728, PED-5853, PED-6079, PED-6252, PED-7542, PED-7619, PED-8111, PED-8240
Maintenance Incident: [SUSE:Maintenance:34127](https://smelt.suse.de/incident/34127/)
Sources used:
openSUSE Leap 15.6 (src):
 kernel-syms-azure-6.4.0-150600.8.5.1, kernel-source-azure-6.4.0-150600.8.5.4
Public Cloud Module 15-SP6 (src):
 kernel-syms-azure-6.4.0-150600.8.5.1, kernel-source-azure-6.4.0-150600.8.5.4

NOTE: This line indicates an update has been released for the listed product(s). At times this might be only a partial fix. If you have questions please reach out to maintenance coordination.