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-rw-r--r--net/core/filter.c231
1 files changed, 72 insertions, 159 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index 23e9b2a6b4c8..03dc0710194f 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -383,7 +383,57 @@ EXPORT_SYMBOL(sk_run_filter);
*/
int sk_chk_filter(struct sock_filter *filter, int flen)
{
- struct sock_filter *ftest;
+ /*
+ * Valid instructions are initialized to non-0.
+ * Invalid instructions are initialized to 0.
+ */
+ static const u8 codes[] = {
+ [BPF_ALU|BPF_ADD|BPF_K] = BPF_S_ALU_ADD_K + 1,
+ [BPF_ALU|BPF_ADD|BPF_X] = BPF_S_ALU_ADD_X + 1,
+ [BPF_ALU|BPF_SUB|BPF_K] = BPF_S_ALU_SUB_K + 1,
+ [BPF_ALU|BPF_SUB|BPF_X] = BPF_S_ALU_SUB_X + 1,
+ [BPF_ALU|BPF_MUL|BPF_K] = BPF_S_ALU_MUL_K + 1,
+ [BPF_ALU|BPF_MUL|BPF_X] = BPF_S_ALU_MUL_X + 1,
+ [BPF_ALU|BPF_DIV|BPF_X] = BPF_S_ALU_DIV_X + 1,
+ [BPF_ALU|BPF_AND|BPF_K] = BPF_S_ALU_AND_K + 1,
+ [BPF_ALU|BPF_AND|BPF_X] = BPF_S_ALU_AND_X + 1,
+ [BPF_ALU|BPF_OR|BPF_K] = BPF_S_ALU_OR_K + 1,
+ [BPF_ALU|BPF_OR|BPF_X] = BPF_S_ALU_OR_X + 1,
+ [BPF_ALU|BPF_LSH|BPF_K] = BPF_S_ALU_LSH_K + 1,
+ [BPF_ALU|BPF_LSH|BPF_X] = BPF_S_ALU_LSH_X + 1,
+ [BPF_ALU|BPF_RSH|BPF_K] = BPF_S_ALU_RSH_K + 1,
+ [BPF_ALU|BPF_RSH|BPF_X] = BPF_S_ALU_RSH_X + 1,
+ [BPF_ALU|BPF_NEG] = BPF_S_ALU_NEG + 1,
+ [BPF_LD|BPF_W|BPF_ABS] = BPF_S_LD_W_ABS + 1,
+ [BPF_LD|BPF_H|BPF_ABS] = BPF_S_LD_H_ABS + 1,
+ [BPF_LD|BPF_B|BPF_ABS] = BPF_S_LD_B_ABS + 1,
+ [BPF_LD|BPF_W|BPF_LEN] = BPF_S_LD_W_LEN + 1,
+ [BPF_LD|BPF_W|BPF_IND] = BPF_S_LD_W_IND + 1,
+ [BPF_LD|BPF_H|BPF_IND] = BPF_S_LD_H_IND + 1,
+ [BPF_LD|BPF_B|BPF_IND] = BPF_S_LD_B_IND + 1,
+ [BPF_LD|BPF_IMM] = BPF_S_LD_IMM + 1,
+ [BPF_LDX|BPF_W|BPF_LEN] = BPF_S_LDX_W_LEN + 1,
+ [BPF_LDX|BPF_B|BPF_MSH] = BPF_S_LDX_B_MSH + 1,
+ [BPF_LDX|BPF_IMM] = BPF_S_LDX_IMM + 1,
+ [BPF_MISC|BPF_TAX] = BPF_S_MISC_TAX + 1,
+ [BPF_MISC|BPF_TXA] = BPF_S_MISC_TXA + 1,
+ [BPF_RET|BPF_K] = BPF_S_RET_K + 1,
+ [BPF_RET|BPF_A] = BPF_S_RET_A + 1,
+ [BPF_ALU|BPF_DIV|BPF_K] = BPF_S_ALU_DIV_K + 1,
+ [BPF_LD|BPF_MEM] = BPF_S_LD_MEM + 1,
+ [BPF_LDX|BPF_MEM] = BPF_S_LDX_MEM + 1,
+ [BPF_ST] = BPF_S_ST + 1,
+ [BPF_STX] = BPF_S_STX + 1,
+ [BPF_JMP|BPF_JA] = BPF_S_JMP_JA + 1,
+ [BPF_JMP|BPF_JEQ|BPF_K] = BPF_S_JMP_JEQ_K + 1,
+ [BPF_JMP|BPF_JEQ|BPF_X] = BPF_S_JMP_JEQ_X + 1,
+ [BPF_JMP|BPF_JGE|BPF_K] = BPF_S_JMP_JGE_K + 1,
+ [BPF_JMP|BPF_JGE|BPF_X] = BPF_S_JMP_JGE_X + 1,
+ [BPF_JMP|BPF_JGT|BPF_K] = BPF_S_JMP_JGT_K + 1,
+ [BPF_JMP|BPF_JGT|BPF_X] = BPF_S_JMP_JGT_X + 1,
+ [BPF_JMP|BPF_JSET|BPF_K] = BPF_S_JMP_JSET_K + 1,
+ [BPF_JMP|BPF_JSET|BPF_X] = BPF_S_JMP_JSET_X + 1,
+ };
int pc;
if (flen == 0 || flen > BPF_MAXINSNS)
@@ -391,136 +441,31 @@ int sk_chk_filter(struct sock_filter *filter, int flen)
/* check the filter code now */
for (pc = 0; pc < flen; pc++) {
- ftest = &filter[pc];
-
- /* Only allow valid instructions */
- switch (ftest->code) {
- case BPF_ALU|BPF_ADD|BPF_K:
- ftest->code = BPF_S_ALU_ADD_K;
- break;
- case BPF_ALU|BPF_ADD|BPF_X:
- ftest->code = BPF_S_ALU_ADD_X;
- break;
- case BPF_ALU|BPF_SUB|BPF_K:
- ftest->code = BPF_S_ALU_SUB_K;
- break;
- case BPF_ALU|BPF_SUB|BPF_X:
- ftest->code = BPF_S_ALU_SUB_X;
- break;
- case BPF_ALU|BPF_MUL|BPF_K:
- ftest->code = BPF_S_ALU_MUL_K;
- break;
- case BPF_ALU|BPF_MUL|BPF_X:
- ftest->code = BPF_S_ALU_MUL_X;
- break;
- case BPF_ALU|BPF_DIV|BPF_X:
- ftest->code = BPF_S_ALU_DIV_X;
- break;
- case BPF_ALU|BPF_AND|BPF_K:
- ftest->code = BPF_S_ALU_AND_K;
- break;
- case BPF_ALU|BPF_AND|BPF_X:
- ftest->code = BPF_S_ALU_AND_X;
- break;
- case BPF_ALU|BPF_OR|BPF_K:
- ftest->code = BPF_S_ALU_OR_K;
- break;
- case BPF_ALU|BPF_OR|BPF_X:
- ftest->code = BPF_S_ALU_OR_X;
- break;
- case BPF_ALU|BPF_LSH|BPF_K:
- ftest->code = BPF_S_ALU_LSH_K;
- break;
- case BPF_ALU|BPF_LSH|BPF_X:
- ftest->code = BPF_S_ALU_LSH_X;
- break;
- case BPF_ALU|BPF_RSH|BPF_K:
- ftest->code = BPF_S_ALU_RSH_K;
- break;
- case BPF_ALU|BPF_RSH|BPF_X:
- ftest->code = BPF_S_ALU_RSH_X;
- break;
- case BPF_ALU|BPF_NEG:
- ftest->code = BPF_S_ALU_NEG;
- break;
- case BPF_LD|BPF_W|BPF_ABS:
- ftest->code = BPF_S_LD_W_ABS;
- break;
- case BPF_LD|BPF_H|BPF_ABS:
- ftest->code = BPF_S_LD_H_ABS;
- break;
- case BPF_LD|BPF_B|BPF_ABS:
- ftest->code = BPF_S_LD_B_ABS;
- break;
- case BPF_LD|BPF_W|BPF_LEN:
- ftest->code = BPF_S_LD_W_LEN;
- break;
- case BPF_LD|BPF_W|BPF_IND:
- ftest->code = BPF_S_LD_W_IND;
- break;
- case BPF_LD|BPF_H|BPF_IND:
- ftest->code = BPF_S_LD_H_IND;
- break;
- case BPF_LD|BPF_B|BPF_IND:
- ftest->code = BPF_S_LD_B_IND;
- break;
- case BPF_LD|BPF_IMM:
- ftest->code = BPF_S_LD_IMM;
- break;
- case BPF_LDX|BPF_W|BPF_LEN:
- ftest->code = BPF_S_LDX_W_LEN;
- break;
- case BPF_LDX|BPF_B|BPF_MSH:
- ftest->code = BPF_S_LDX_B_MSH;
- break;
- case BPF_LDX|BPF_IMM:
- ftest->code = BPF_S_LDX_IMM;
- break;
- case BPF_MISC|BPF_TAX:
- ftest->code = BPF_S_MISC_TAX;
- break;
- case BPF_MISC|BPF_TXA:
- ftest->code = BPF_S_MISC_TXA;
- break;
- case BPF_RET|BPF_K:
- ftest->code = BPF_S_RET_K;
- break;
- case BPF_RET|BPF_A:
- ftest->code = BPF_S_RET_A;
- break;
+ struct sock_filter *ftest = &filter[pc];
+ u16 code = ftest->code;
+ if (code >= ARRAY_SIZE(codes))
+ return -EINVAL;
+ code = codes[code];
+ /* Undo the '+ 1' in codes[] after validation. */
+ if (!code--)
+ return -EINVAL;
/* Some instructions need special checks */
-
+ switch (code) {
+ case BPF_S_ALU_DIV_K:
/* check for division by zero */
- case BPF_ALU|BPF_DIV|BPF_K:
if (ftest->k == 0)
return -EINVAL;
- ftest->code = BPF_S_ALU_DIV_K;
break;
-
- /* check for invalid memory addresses */
- case BPF_LD|BPF_MEM:
- if (ftest->k >= BPF_MEMWORDS)
- return -EINVAL;
- ftest->code = BPF_S_LD_MEM;
- break;
- case BPF_LDX|BPF_MEM:
- if (ftest->k >= BPF_MEMWORDS)
- return -EINVAL;
- ftest->code = BPF_S_LDX_MEM;
- break;
- case BPF_ST:
- if (ftest->k >= BPF_MEMWORDS)
- return -EINVAL;
- ftest->code = BPF_S_ST;
- break;
- case BPF_STX:
+ case BPF_S_LD_MEM:
+ case BPF_S_LDX_MEM:
+ case BPF_S_ST:
+ case BPF_S_STX:
+ /* check for invalid memory addresses */
if (ftest->k >= BPF_MEMWORDS)
return -EINVAL;
- ftest->code = BPF_S_STX;
break;
-
- case BPF_JMP|BPF_JA:
+ case BPF_S_JMP_JA:
/*
* Note, the large ftest->k might cause loops.
* Compare this with conditional jumps below,
@@ -528,40 +473,7 @@ int sk_chk_filter(struct sock_filter *filter, int flen)
*/
if (ftest->k >= (unsigned)(flen-pc-1))
return -EINVAL;
- ftest->code = BPF_S_JMP_JA;
- break;
-
- case BPF_JMP|BPF_JEQ|BPF_K:
- ftest->code = BPF_S_JMP_JEQ_K;
- break;
- case BPF_JMP|BPF_JEQ|BPF_X:
- ftest->code = BPF_S_JMP_JEQ_X;
break;
- case BPF_JMP|BPF_JGE|BPF_K:
- ftest->code = BPF_S_JMP_JGE_K;
- break;
- case BPF_JMP|BPF_JGE|BPF_X:
- ftest->code = BPF_S_JMP_JGE_X;
- break;
- case BPF_JMP|BPF_JGT|BPF_K:
- ftest->code = BPF_S_JMP_JGT_K;
- break;
- case BPF_JMP|BPF_JGT|BPF_X:
- ftest->code = BPF_S_JMP_JGT_X;
- break;
- case BPF_JMP|BPF_JSET|BPF_K:
- ftest->code = BPF_S_JMP_JSET_K;
- break;
- case BPF_JMP|BPF_JSET|BPF_X:
- ftest->code = BPF_S_JMP_JSET_X;
- break;
-
- default:
- return -EINVAL;
- }
-
- /* for conditionals both must be safe */
- switch (ftest->code) {
case BPF_S_JMP_JEQ_K:
case BPF_S_JMP_JEQ_X:
case BPF_S_JMP_JGE_K:
@@ -570,10 +482,13 @@ int sk_chk_filter(struct sock_filter *filter, int flen)
case BPF_S_JMP_JGT_X:
case BPF_S_JMP_JSET_X:
case BPF_S_JMP_JSET_K:
+ /* for conditionals both must be safe */
if (pc + ftest->jt + 1 >= flen ||
pc + ftest->jf + 1 >= flen)
return -EINVAL;
+ break;
}
+ ftest->code = code;
}
/* last instruction must be a RET code */
@@ -581,10 +496,8 @@ int sk_chk_filter(struct sock_filter *filter, int flen)
case BPF_S_RET_K:
case BPF_S_RET_A:
return 0;
- break;
- default:
- return -EINVAL;
- }
+ }
+ return -EINVAL;
}
EXPORT_SYMBOL(sk_chk_filter);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.