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Commit ed4afd45 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by David S. Miller
Browse files

tools: bpf_jit_disasm: ignore image address for disasm 



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: default avatarAlexei Starovoitov <ast@plumgrid.com>
Acked-by: default avatarDaniel Borkmann <dborkman@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e0a1272c

tools/net/bpf_jit_disasm.c

+8 −10
Original line number Diff line number Diff line
@@ -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);