redonkable/remarkable-linux
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tools: bpf_jit_disasm: ignore image address for disasm

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seccomp filters use kernel JIT image addresses, so bpf_jit_enable=2 prints
[ 20.146438] flen=3 proglen=82 pass=0 image=0000000000000000
[ 20.146442] JIT code: 00000000: 55 48 89 e5 48 81 ec 28 02 00 00 ...

ignore image address, so that seccomp filters can be disassembled

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Alexei Starovoitov 2014-05-15 15:56:38 -07:00 committed by David S. Miller
parent e0a1272cfa
commit ed4afd451f
1 changed files with 8 additions and 10 deletions
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18
tools/net/bpf_jit_disasm.c
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@ -43,8 +43,7 @@ static void get_exec_path(char *tpath, size_t size)
free(path);
}
static void get_asm_insns(uint8_t *image, size_t len, unsigned long base,
int opcodes)
static void get_asm_insns(uint8_t *image, size_t len, int opcodes)
{
int count, i, pc = 0;
char tpath[256];
@ -107,13 +106,13 @@ static void put_klog_buff(char *buff)
}
static int get_last_jit_image(char *haystack, size_t hlen,
uint8_t *image, size_t ilen,
unsigned long *base)
uint8_t *image, size_t ilen)
{
char *ptr, *pptr, *tmp;
off_t off = 0;
int ret, flen, proglen, pass, ulen = 0;
regmatch_t pmatch[1];
unsigned long base;
regex_t regex;
if (hlen == 0)
@ -136,7 +135,7 @@ static int get_last_jit_image(char *haystack, size_t hlen,
ptr = haystack + off - (pmatch[0].rm_eo - pmatch[0].rm_so);
ret = sscanf(ptr, "flen=%d proglen=%d pass=%d image=%lx",
&flen, &proglen, &pass, base);
&flen, &proglen, &pass, &base);
if (ret != 4)
return 0;
@ -162,7 +161,7 @@ static int get_last_jit_image(char *haystack, size_t hlen,
assert(ulen == proglen);
printf("%d bytes emitted from JIT compiler (pass:%d, flen:%d)\n",
proglen, pass, flen);
printf("%lx + <x>:\n", *base);
printf("%lx + <x>:\n", base);
regfree(&regex);
return ulen;
@ -172,7 +171,6 @@ int main(int argc, char **argv)
{
int len, klen, opcodes = 0;
char *kbuff;
unsigned long base;
uint8_t image[4096];
if (argc > 1) {
@ -189,9 +187,9 @@ int main(int argc, char **argv)
kbuff = get_klog_buff(&klen);
len = get_last_jit_image(kbuff, klen, image, sizeof(image), &base);
if (len > 0 && base > 0)
get_asm_insns(image, len, base, opcodes);
len = get_last_jit_image(kbuff, klen, image, sizeof(image));
if (len > 0)
get_asm_insns(image, len, opcodes);
put_klog_buff(kbuff);