diff options
| author | Alexey Brodkin <Alexey.Brodkin@synopsys.com> | 2015-03-12 02:21:12 +0300 |
|---|---|---|
| committer | Bernhard Reutner-Fischer <rep.dot.nop@gmail.com> | 2015-03-16 11:06:18 +0100 |
| commit | 8ee422cffbfd3e2a16265fe6680a8dde2f5e58fe (patch) | |
| tree | 6b419d566ff72881e062a4641a9ee35a7a52b44e /libc/inet | |
| parent | 21cbb6fe887a30f0777521ec10f0d0d9c2a7da7e (diff) | |
resolv: fix unaligned tmp buffer corner-case
On execution of "inet/gethost_r-align" test I noticed failure due
to unaligned access (instaed of 4-byte aligned 1-byte aligned
address was attempted to be accessed).
Further investigation confirmed this nice and helpful test failure.
Following commit removed usage of ALIGN_BUFFER_OFFSET on entry to
__read_etc_hosts_r():
http://git.uclibc.org/uClibc/commit/?id=f65e66078b9f4d2d7f0fc336dee36e78fc467c0f
So indeed if target architecture doesn't allow unaligned access
and provided tmp buffer is not word aligned (and we will deal with pointers
which means word-sized data units), then CPU will fail during execution.
In case of ARC we'll see "Unaligned access" exception like this:
--->8---
# potentially unexpected fatal signal 7.
Path: /root/uClibc/test/inet/gethost_r-align
CPU: 0 PID: 5514 Comm: gethost_r-align Not tainted 3.13.11 #2
task: 8f42a580 ti: 8f40e000 task.ti: 8f40e000
[ECR ]: 0x00230400 => Misaligned r/w from 0x5fdab341
[EFA ]: 0x5fdab341
[BLINK ]: 0x20032a18
[ERET ]: 0x20032a3c
@off 0x12a3c in [/lib/libuClibc-0.9.34-git.so]
VMA: 0x20020000 to 0x20062000
[STAT32]: 0x00000086 : U E2 E1
BTA: 0x20046014 SP: 0x5fdab260 FP: 0x00000000
LPS: 0x20046064 LPE: 0x20046068 LPC: 0x00000000
r00: 0x5fdab341 r01: 0x00000005 r02: 0x00000015
r03: 0x00000000 r04: 0x5fdab358 r05: 0x00000000
r06: 0x0a0a0a00 r07: 0x00000000 r08: 0x0000003f
r09: 0x20067050 r10: 0x00000000 r11: 0x00000014
r12: 0x00000001 r13: 0x00000000 r14: 0x20060660
r15: 0x20060661 r16: 0x00000006 r17: 0x5fdab371
r18: 0x00000018 r19: 0x5fdab2b4 r20: 0x00020000
r21: 0x00000000 r22: 0x00029068 r23: 0x5fdab371
r24: 0x00010000 r25: 0x00000000
--->8---
To fix this problem we'll re-introduce tmp buffer force alignment
before config parser invocation.
Signed-off-by: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Waldemar Brodkorb <wbx@openadk.org>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
Diffstat (limited to 'libc/inet')
| -rw-r--r-- | libc/inet/resolv.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/libc/inet/resolv.c b/libc/inet/resolv.c index cfc1eee9b..31e63810b 100644 --- a/libc/inet/resolv.c +++ b/libc/inet/resolv.c @@ -1615,9 +1615,13 @@ int __read_etc_hosts_r( #endif ; int ret = HOST_NOT_FOUND; + /* make sure pointer is aligned */ + int i = ALIGN_BUFFER_OFFSET(buf); + buf += i; + buflen -= i; *h_errnop = NETDB_INTERNAL; - if (buflen < aliaslen + if (/* (ssize_t)buflen < 0 || */ buflen < aliaslen || (buflen - aliaslen) < BUFSZ + 1) return ERANGE; if (parser == NULL) |