kernel/linux.git/lib, branch v3.16.61

string: provide strscpy()

2018-10-21T07:46:12+00:00

commit 30035e45753b708e7d47a98398500ca005e02b86 upstream. The strscpy() API is intended to be used instead of strlcpy(), and instead of most uses of strncpy(). - Unlike strlcpy(), it doesn't read from memory beyond (src + size). - Unlike strlcpy() or strncpy(), the API provides an easy way to check for destination buffer overflow: an -E2BIG error return value. - The provided implementation is robust in the face of the source buffer being asynchronously changed during the copy, unlike the current implementation of strlcpy(). - Unlike strncpy(), the destination buffer will be NUL-terminated if the string in the source buffer is too long. - Also unlike strncpy(), the destination buffer will not be updated beyond the NUL termination, avoiding strncpy's behavior of zeroing the entire tail end of the destination buffer. (A memset() after the strscpy() can be used if this behavior is desired.) - The implementation should be reasonably performant on all platforms since it uses the asm/word-at-a-time.h API rather than simple byte copy. Kernel-to-kernel string copy is not considered to be performance critical in any case. Signed-off-by: Chris Metcalf [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings

509: fix printing uninitialized stack memory when OID is empty

2018-03-03T15:51:49+00:00

commit 8dfd2f22d3bf3ab7714f7495ad5d897b8845e8c1 upstream. Callers of sprint_oid() do not check its return value before printing the result. In the case where the OID is zero-length, -EBADMSG was being returned without anything being written to the buffer, resulting in uninitialized stack memory being printed. Fix this by writing "(bad)" to the buffer in the cases where -EBADMSG is returned. Fixes: 4f73175d0375 ("X.509: Add utility functions to render OIDs as strings") Signed-off-by: Eric Biggers Signed-off-by: David Howells Signed-off-by: Ben Hutchings

X.509: fix buffer overflow detection in sprint_oid()

2018-03-03T15:51:49+00:00

commit 47e0a208fb9d91e3f3c86309e752b13a36470ae8 upstream. In sprint_oid(), if the input buffer were to be more than 1 byte too small for the first snprintf(), 'bufsize' would underflow, causing a buffer overflow when printing the remainder of the OID. Fortunately this cannot actually happen currently, because no users pass in a buffer that can be too small for the first snprintf(). Regardless, fix it by checking the snprintf() return value correctly. For consistency also tweak the second snprintf() check to look the same. Fixes: 4f73175d0375 ("X.509: Add utility functions to render OIDs as strings") Cc: Takashi Iwai Signed-off-by: Eric Biggers Signed-off-by: David Howells Reviewed-by: James Morris Signed-off-by: Ben Hutchings

lib/oid_registry.c: X.509: fix the buffer overflow in the utility function for OID string

2018-03-03T15:51:49+00:00

commit afdb05e9d61905220f09268535235288e6ba3a16 upstream. The sprint_oid() utility function doesn't properly check the buffer size that it causes that the warning in vsnprintf() be triggered. For example on v4.1 kernel: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 2357 at lib/vsprintf.c:1867 vsnprintf+0x5a7/0x5c0() ... We can trigger this issue by injecting maliciously crafted x509 cert in DER format. Just using hex editor to change the length of OID to over the length of the SEQUENCE container. For example: 0:d=0 hl=4 l= 980 cons: SEQUENCE 4:d=1 hl=4 l= 700 cons: SEQUENCE 8:d=2 hl=2 l= 3 cons: cont [ 0 ] 10:d=3 hl=2 l= 1 prim: INTEGER :02 13:d=2 hl=2 l= 9 prim: INTEGER :9B47FAF791E7D1E3 24:d=2 hl=2 l= 13 cons: SEQUENCE 26:d=3 hl=2 l= 9 prim: OBJECT :sha256WithRSAEncryption 37:d=3 hl=2 l= 0 prim: NULL 39:d=2 hl=2 l= 121 cons: SEQUENCE 41:d=3 hl=2 l= 22 cons: SET 43:d=4 hl=2 l= 20 cons: SEQUENCE <=== the SEQ length is 20 45:d=5 hl=2 l= 3 prim: OBJECT :organizationName <=== the original length is 3, change the length of OID to over the length of SEQUENCE Pawel Wieczorkiewicz reported this problem and Takashi Iwai provided patch to fix it by checking the bufsize in sprint_oid(). Link: http://lkml.kernel.org/r/20170903021646.2080-1-jlee@suse.com Signed-off-by: Takashi Iwai Signed-off-by: "Lee, Chun-Yi" Reported-by: Pawel Wieczorkiewicz Cc: David Howells Cc: Rusty Russell Cc: Pawel Wieczorkiewicz Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings

ASN.1: check for error from ASN1_OP_END__ACT actions

2018-03-03T15:51:48+00:00

commit 81a7be2cd69b412ab6aeacfe5ebf1bb6e5bce955 upstream. asn1_ber_decoder() was ignoring errors from actions associated with the opcodes ASN1_OP_END_SEQ_ACT, ASN1_OP_END_SET_ACT, ASN1_OP_END_SEQ_OF_ACT, and ASN1_OP_END_SET_OF_ACT. In practice, this meant the pkcs7_note_signed_info() action (since that was the only user of those opcodes). Fix it by checking for the error, just like the decoder does for actions associated with the other opcodes. This bug allowed users to leak slab memory by repeatedly trying to add a specially crafted "pkcs7_test" key (requires CONFIG_PKCS7_TEST_KEY). In theory, this bug could also be used to bypass module signature verification, by providing a PKCS#7 message that is misparsed such that a signature's ->authattrs do not contain its ->msgdigest. But it doesn't seem practical in normal cases, due to restrictions on the format of the ->authattrs. Fixes: 42d5ec27f873 ("X.509: Add an ASN.1 decoder") Signed-off-by: Eric Biggers Signed-off-by: David Howells Reviewed-by: James Morris Signed-off-by: Ben Hutchings

ASN.1: fix out-of-bounds read when parsing indefinite length item

2018-03-03T15:51:48+00:00

commit e0058f3a874ebb48b25be7ff79bc3b4e59929f90 upstream. In asn1_ber_decoder(), indefinitely-sized ASN.1 items were being passed to the action functions before their lengths had been computed, using the bogus length of 0x80 (ASN1_INDEFINITE_LENGTH). This resulted in reading data past the end of the input buffer, when given a specially crafted message. Fix it by rearranging the code so that the indefinite length is resolved before the action is called. This bug was originally found by fuzzing the X.509 parser in userspace using libFuzzer from the LLVM project. KASAN report (cleaned up slightly): BUG: KASAN: slab-out-of-bounds in memcpy ./include/linux/string.h:341 [inline] BUG: KASAN: slab-out-of-bounds in x509_fabricate_name.constprop.1+0x1a4/0x940 crypto/asymmetric_keys/x509_cert_parser.c:366 Read of size 128 at addr ffff880035dd9eaf by task keyctl/195 CPU: 1 PID: 195 Comm: keyctl Not tainted 4.14.0-09238-g1d3b78bbc6e9 #26 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-20171110_100015-anatol 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xd1/0x175 lib/dump_stack.c:53 print_address_description+0x78/0x260 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report+0x23f/0x350 mm/kasan/report.c:409 memcpy+0x1f/0x50 mm/kasan/kasan.c:302 memcpy ./include/linux/string.h:341 [inline] x509_fabricate_name.constprop.1+0x1a4/0x940 crypto/asymmetric_keys/x509_cert_parser.c:366 asn1_ber_decoder+0xb4a/0x1fd0 lib/asn1_decoder.c:447 x509_cert_parse+0x1c7/0x620 crypto/asymmetric_keys/x509_cert_parser.c:89 x509_key_preparse+0x61/0x750 crypto/asymmetric_keys/x509_public_key.c:174 asymmetric_key_preparse+0xa4/0x150 crypto/asymmetric_keys/asymmetric_type.c:388 key_create_or_update+0x4d4/0x10a0 security/keys/key.c:850 SYSC_add_key security/keys/keyctl.c:122 [inline] SyS_add_key+0xe8/0x290 security/keys/keyctl.c:62 entry_SYSCALL_64_fastpath+0x1f/0x96 Allocated by task 195: __do_kmalloc_node mm/slab.c:3675 [inline] __kmalloc_node+0x47/0x60 mm/slab.c:3682 kvmalloc ./include/linux/mm.h:540 [inline] SYSC_add_key security/keys/keyctl.c:104 [inline] SyS_add_key+0x19e/0x290 security/keys/keyctl.c:62 entry_SYSCALL_64_fastpath+0x1f/0x96 Fixes: 42d5ec27f873 ("X.509: Add an ASN.1 decoder") Reported-by: Alexander Potapenko Signed-off-by: Eric Biggers Signed-off-by: David Howells [bwh: Backported to 3.16: drop ASN1_OP_{COND_,}MATCH_ANY_{ACT_,}OR_SKIP cases] Signed-off-by: Ben Hutchings

lib/int_sqrt: optimize small argument

2018-02-13T18:42:25+00:00

commit 3f3295709edea6268ff1609855f498035286af73 upstream. The current int_sqrt() computation is sub-optimal for the case of small @x. Which is the interesting case when we're going to do cumulative distribution functions on idle times, which we assume to be a random variable, where the target residency of the deepest idle state gives an upper bound on the variable (5e6ns on recent Intel chips). In the case of small @x, the compute loop: while (m != 0) { b = y + m; y >>= 1; if (x >= b) { x -= b; y += m; } m >>= 2; } can be reduced to: while (m > x) m >>= 2; Because y==0, b==m and until x>=m y will remain 0. And while this is computationally equivalent, it runs much faster because there's less code, in particular less branches. cycles: branches: branch-misses: OLD: hot: 45.109444 +- 0.044117 44.333392 +- 0.002254 0.018723 +- 0.000593 cold: 187.737379 +- 0.156678 44.333407 +- 0.002254 6.272844 +- 0.004305 PRE: hot: 67.937492 +- 0.064124 66.999535 +- 0.000488 0.066720 +- 0.001113 cold: 232.004379 +- 0.332811 66.999527 +- 0.000488 6.914634 +- 0.006568 POST: hot: 43.633557 +- 0.034373 45.333132 +- 0.002277 0.023529 +- 0.000681 cold: 207.438411 +- 0.125840 45.333132 +- 0.002277 6.976486 +- 0.004219 Averages computed over all values <128k using a LFSR to generate order. Cold numbers have a LFSR based branch trace buffer 'confuser' ran between each int_sqrt() invocation. Link: http://lkml.kernel.org/r/20171020164644.876503355@infradead.org Fixes: 30493cc9dddb ("lib/int_sqrt.c: optimize square root algorithm") Signed-off-by: Peter Zijlstra (Intel) Suggested-by: Anshul Garg Acked-by: Linus Torvalds Cc: Davidlohr Bueso Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Will Deacon Cc: Joe Perches Cc: David Miller Cc: Matthew Wilcox Cc: Kees Cook Cc: Michael Davidson Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings

KEYS: fix NULL pointer dereference during ASN.1 parsing [ver #2]

2018-01-01T20:52:06+00:00

commit 624f5ab8720b3371367327a822c267699c1823b8 upstream. syzkaller reported a NULL pointer dereference in asn1_ber_decoder(). It can be reproduced by the following command, assuming CONFIG_PKCS7_TEST_KEY=y: keyctl add pkcs7_test desc '' @s The bug is that if the data buffer is empty, an integer underflow occurs in the following check: if (unlikely(dp >= datalen - 1)) goto data_overrun_error; This results in the NULL data pointer being dereferenced. Fix it by checking for 'datalen - dp < 2' instead. Also fix the similar check for 'dp >= datalen - n' later in the same function. That one possibly could result in a buffer overread. The NULL pointer dereference was reproducible using the "pkcs7_test" key type but not the "asymmetric" key type because the "asymmetric" key type checks for a 0-length payload before calling into the ASN.1 decoder but the "pkcs7_test" key type does not. The bug report was: BUG: unable to handle kernel NULL pointer dereference at (null) IP: asn1_ber_decoder+0x17f/0xe60 lib/asn1_decoder.c:233 PGD 7b708067 P4D 7b708067 PUD 7b6ee067 PMD 0 Oops: 0000 [#1] SMP Modules linked in: CPU: 0 PID: 522 Comm: syz-executor1 Not tainted 4.14.0-rc8 #7 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.3-20171021_125229-anatol 04/01/2014 task: ffff9b6b3798c040 task.stack: ffff9b6b37970000 RIP: 0010:asn1_ber_decoder+0x17f/0xe60 lib/asn1_decoder.c:233 RSP: 0018:ffff9b6b37973c78 EFLAGS: 00010216 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000000000021c RDX: ffffffff814a04ed RSI: ffffb1524066e000 RDI: ffffffff910759e0 RBP: ffff9b6b37973d60 R08: 0000000000000001 R09: ffff9b6b3caa4180 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f10ed1f2700(0000) GS:ffff9b6b3ea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000007b6f3000 CR4: 00000000000006f0 Call Trace: pkcs7_parse_message+0xee/0x240 crypto/asymmetric_keys/pkcs7_parser.c:139 verify_pkcs7_signature+0x33/0x180 certs/system_keyring.c:216 pkcs7_preparse+0x41/0x70 crypto/asymmetric_keys/pkcs7_key_type.c:63 key_create_or_update+0x180/0x530 security/keys/key.c:855 SYSC_add_key security/keys/keyctl.c:122 [inline] SyS_add_key+0xbf/0x250 security/keys/keyctl.c:62 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x4585c9 RSP: 002b:00007f10ed1f1bd8 EFLAGS: 00000216 ORIG_RAX: 00000000000000f8 RAX: ffffffffffffffda RBX: 00007f10ed1f2700 RCX: 00000000004585c9 RDX: 0000000020000000 RSI: 0000000020008ffb RDI: 0000000020008000 RBP: 0000000000000000 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000216 R12: 00007fff1b2260ae R13: 00007fff1b2260af R14: 00007f10ed1f2700 R15: 0000000000000000 Code: dd ca ff 48 8b 45 88 48 83 e8 01 4c 39 f0 0f 86 a8 07 00 00 e8 53 dd ca ff 49 8d 46 01 48 89 85 58 ff ff ff 48 8b 85 60 ff ff ff <42> 0f b6 0c 30 89 c8 88 8d 75 ff ff ff 83 e0 1f 89 8d 28 ff ff RIP: asn1_ber_decoder+0x17f/0xe60 lib/asn1_decoder.c:233 RSP: ffff9b6b37973c78 CR2: 0000000000000000 Fixes: 42d5ec27f873 ("X.509: Add an ASN.1 decoder") Reported-by: syzbot Signed-off-by: Eric Biggers Signed-off-by: David Howells Signed-off-by: James Morris Signed-off-by: Ben Hutchings

KEYS: fix out-of-bounds read during ASN.1 parsing

2018-01-01T20:52:03+00:00

commit 2eb9eabf1e868fda15808954fb29b0f105ed65f1 upstream. syzkaller with KASAN reported an out-of-bounds read in asn1_ber_decoder(). It can be reproduced by the following command, assuming CONFIG_X509_CERTIFICATE_PARSER=y and CONFIG_KASAN=y: keyctl add asymmetric desc $'\x30\x30' @s The bug is that the length of an ASN.1 data value isn't validated in the case where it is encoded using the short form, causing the decoder to read past the end of the input buffer. Fix it by validating the length. The bug report was: BUG: KASAN: slab-out-of-bounds in asn1_ber_decoder+0x10cb/0x1730 lib/asn1_decoder.c:233 Read of size 1 at addr ffff88003cccfa02 by task syz-executor0/6818 CPU: 1 PID: 6818 Comm: syz-executor0 Not tainted 4.14.0-rc7-00008-g5f479447d983 #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0xb3/0x10b lib/dump_stack.c:52 print_address_description+0x79/0x2a0 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report+0x236/0x340 mm/kasan/report.c:409 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:427 asn1_ber_decoder+0x10cb/0x1730 lib/asn1_decoder.c:233 x509_cert_parse+0x1db/0x650 crypto/asymmetric_keys/x509_cert_parser.c:89 x509_key_preparse+0x64/0x7a0 crypto/asymmetric_keys/x509_public_key.c:174 asymmetric_key_preparse+0xcb/0x1a0 crypto/asymmetric_keys/asymmetric_type.c:388 key_create_or_update+0x347/0xb20 security/keys/key.c:855 SYSC_add_key security/keys/keyctl.c:122 [inline] SyS_add_key+0x1cd/0x340 security/keys/keyctl.c:62 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x447c89 RSP: 002b:00007fca7a5d3bd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000f8 RAX: ffffffffffffffda RBX: 00007fca7a5d46cc RCX: 0000000000447c89 RDX: 0000000020006f4a RSI: 0000000020006000 RDI: 0000000020001ff5 RBP: 0000000000000046 R08: fffffffffffffffd R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fca7a5d49c0 R15: 00007fca7a5d4700 Fixes: 42d5ec27f873 ("X.509: Add an ASN.1 decoder") Signed-off-by: Eric Biggers Signed-off-by: David Howells Signed-off-by: James Morris Signed-off-by: Ben Hutchings

lib/digsig: fix dereference of NULL user_key_payload

2018-01-01T20:51:52+00:00

commit 192cabd6a296cbc57b3d8c05c4c89d87fc102506 upstream. digsig_verify() requests a user key, then accesses its payload. However, a revoked key has a NULL payload, and we failed to check for this. request_key() *does* skip revoked keys, but there is still a window where the key can be revoked before we acquire its semaphore. Fix it by checking for a NULL payload, treating it like a key which was already revoked at the time it was requested. Fixes: 051dbb918c7f ("crypto: digital signature verification support") Reviewed-by: James Morris Cc: Dmitry Kasatkin Signed-off-by: Eric Biggers Signed-off-by: David Howells [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings