Dear developers and maintainers, We encountered a warning in function sel_write_load(). It is tested on kernel 6.8.0-rc7. Bug report is listed below. ``` WARNING: CPU: 1 PID: 8109 at mm/vmalloc.c:3247 __vmalloc_node_range+0x10a0/0x1490 mm/vmalloc.c:3247 Modules linked in: CPU: 1 PID: 8109 Comm: syz-executor370 Not tainted 6.7.0-rc7 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:__vmalloc_node_range+0x10a0/0x1490 mm/vmalloc.c:3247 Code: 65 48 2b 04 25 28 00 00 00 0f 85 98 02 00 00 48 81 c4 70 01 00 00 4c 89 e0 5b 5d 41 5c 41 5d 41 5e 41 5f c3 e8 71 43 b7 ff 90 <0f> 0b 90 45 31 e4 eb a1 e8 63 43 b7 ff 48 8b 4c 24 40 31 f6 45 31 RSP: 0018:ffffc90002adf9c0 EFLAGS: 00010293 RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffffffff81cdc194 RDX: ffff888022124ec0 RSI: ffffffff81cdd16f RDI: 0000000000000007 RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: ffff888107373a48 R13: dffffc0000000000 R14: 0000000000000000 R15: ffffc90002adfec8 FS: 00005555560953c0(0000) GS:ffff888135c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000010 CR3: 000000010503d000 CR4: 0000000000750ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <TASK> __vmalloc_node mm/vmalloc.c:3385 [inline] vmalloc+0x6b/0x80 mm/vmalloc.c:3418 sel_write_load+0x27f/0x19d0 security/selinux/selinuxfs.c:603 vfs_write+0x2a9/0xd80 fs/read_write.c:582 ksys_pwrite64 fs/read_write.c:699 [inline] __do_sys_pwrite64 fs/read_write.c:709 [inline] __se_sys_pwrite64 fs/read_write.c:706 [inline] __x64_sys_pwrite64+0x1f3/0x250 fs/read_write.c:706 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7f40e7728f8d Code: 28 c3 e8 46 1e 00 00 66 0f 1f 44 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff5bf39508 EFLAGS: 00000246 ORIG_RAX: 0000000000000012 RAX: ffffffffffffffda RBX: 00007fff5bf39708 RCX: 00007f40e7728f8d RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000000001 R08: 0000000000000000 R09: 00007fff5bf39708 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007fff5bf396f8 R14: 00007f40e77a6530 R15: 0000000000000001 </TASK> ``` The cause of this bug is that in sel_write_load(), parameter "count" is controlled by user, which could be zero. It is passed to vmalloc() as an argument. If you have any questions, please contact us. Reported by: Yue Sun <samsun1006219@xxxxxxxxx> Reported by: xingwei lee <xrivendell7@xxxxxxxxx> Best Regards, Yue
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// autogenerated by syzkaller (https://github.com/google/syzkaller) #define _GNU_SOURCE #include <endian.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/syscall.h> #include <sys/types.h> #include <unistd.h> uint64_t r[1] = {0xffffffffffffffff}; int main(void) { syscall(__NR_mmap, /*addr=*/0x1ffff000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x20000000ul, /*len=*/0x1000000ul, /*prot=*/7ul, /*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x21000000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul); intptr_t res = 0; memcpy((void*)0x20000000, "/sys/fs/selinux/load\000", 21); res = syscall(__NR_openat, /*fd=*/0xffffffffffffff9cul, /*file=*/0x20000000ul, /*flags=*/1ul, /*mode=*/0ul); if (res != -1) r[0] = res; syscall(__NR_pwrite64, /*fd=*/r[0], /*buf=*/0ul, /*count=*/0ul, /*pos=*/0ul); return 0; }
