bpf: Take return from set_memory_rox() into account with bpf_jit_binary_lock_ro()

set_memory_rox() can fail, leaving memory unprotected.

Check return and bail out when bpf_jit_binary_lock_ro() returns
an error.

Link: https://github.com/KSPP/linux/issues/7
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: linux-hardening@vger.kernel.org <linux-hardening@vger.kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Puranjay Mohan <puranjay12@gmail.com>
Reviewed-by: Ilya Leoshkevich <iii@linux.ibm.com>  # s390x
Acked-by: Tiezhu Yang <yangtiezhu@loongson.cn>  # LoongArch
Reviewed-by: Johan Almbladh <johan.almbladh@anyfinetworks.com> # MIPS Part
Message-ID: <036b6393f23a2032ce75a1c92220b2afcb798d5d.1709850515.git.christophe.leroy@csgroup.eu>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

arch/arm/net/bpf_jit_32.c

@@ -2222,28 +2222,21 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 	/* If building the body of the JITed code fails somehow,
 	 * we fall back to the interpretation.
 	 */
-	if (build_body(&ctx) < 0) {
+	if (build_body(&ctx) < 0)
-		image_ptr = NULL;
+		goto out_free;
-		bpf_jit_binary_free(header);
-		prog = orig_prog;
-		goto out_imms;
-	}
 	build_epilogue(&ctx);
 
 	/* 3.) Extra pass to validate JITed Code */
-	if (validate_code(&ctx)) {
+	if (validate_code(&ctx))
-		image_ptr = NULL;
+		goto out_free;
-		bpf_jit_binary_free(header);
-		prog = orig_prog;
-		goto out_imms;
-	}
 	flush_icache_range((u32)header, (u32)(ctx.target + ctx.idx));
 
 	if (bpf_jit_enable > 1)
 		/* there are 2 passes here */
 		bpf_jit_dump(prog->len, image_size, 2, ctx.target);
 
-	bpf_jit_binary_lock_ro(header);
+	if (bpf_jit_binary_lock_ro(header))
+		goto out_free;
 	prog->bpf_func = (void *)ctx.target;
 	prog->jited = 1;
 	prog->jited_len = image_size;
@@ -2260,5 +2253,11 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 		bpf_jit_prog_release_other(prog, prog == orig_prog ?
 					   tmp : orig_prog);
 	return prog;
+
+out_free:
+	image_ptr = NULL;
+	bpf_jit_binary_free(header);
+	prog = orig_prog;
+	goto out_imms;
 }
 

arch/loongarch/net/bpf_jit.c

@@ -1294,16 +1294,19 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 	flush_icache_range((unsigned long)header, (unsigned long)(ctx.image + ctx.idx));
 
 	if (!prog->is_func || extra_pass) {
+		int err;
+
 		if (extra_pass && ctx.idx != jit_data->ctx.idx) {
 			pr_err_once("multi-func JIT bug %d != %d\n",
 				    ctx.idx, jit_data->ctx.idx);
-			bpf_jit_binary_free(header);
+			goto out_free;
-			prog->bpf_func = NULL;
+		}
-			prog->jited = 0;
+		err = bpf_jit_binary_lock_ro(header);
-			prog->jited_len = 0;
+		if (err) {
-			goto out_offset;
+			pr_err_once("bpf_jit_binary_lock_ro() returned %d\n",
+				    err);
+			goto out_free;
 		}
-		bpf_jit_binary_lock_ro(header);
 	} else {
 		jit_data->ctx = ctx;
 		jit_data->image = image_ptr;
@@ -1334,6 +1337,13 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 	out_offset = -1;
 
 	return prog;
+
+out_free:
+	bpf_jit_binary_free(header);
+	prog->bpf_func = NULL;
+	prog->jited = 0;
+	prog->jited_len = 0;
+	goto out_offset;
 }
 
 /* Indicate the JIT backend supports mixing bpf2bpf and tailcalls. */

arch/mips/net/bpf_jit_comp.c

@@ -1012,7 +1012,8 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 	bpf_prog_fill_jited_linfo(prog, &ctx.descriptors[1]);
 
 	/* Set as read-only exec and flush instruction cache */
-	bpf_jit_binary_lock_ro(header);
+	if (bpf_jit_binary_lock_ro(header))
+		goto out_err;
 	flush_icache_range((unsigned long)header,
 			   (unsigned long)&ctx.target[ctx.jit_index]);
 

arch/parisc/net/bpf_jit_core.c

@@ -167,7 +167,13 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 	bpf_flush_icache(jit_data->header, ctx->insns + ctx->ninsns);
 
 	if (!prog->is_func || extra_pass) {
-		bpf_jit_binary_lock_ro(jit_data->header);
+		if (bpf_jit_binary_lock_ro(jit_data->header)) {
+			bpf_jit_binary_free(jit_data->header);
+			prog->bpf_func = NULL;
+			prog->jited = 0;
+			prog->jited_len = 0;
+			goto out_offset;
+		}
 		prologue_len = ctx->epilogue_offset - ctx->body_len;
 		for (i = 0; i < prog->len; i++)
 			ctx->offset[i] += prologue_len;

arch/s390/net/bpf_jit_comp.c

@@ -2111,7 +2111,11 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
 		print_fn_code(jit.prg_buf, jit.size_prg);
 	}
 	if (!fp->is_func || extra_pass) {
-		bpf_jit_binary_lock_ro(header);
+		if (bpf_jit_binary_lock_ro(header)) {
+			bpf_jit_binary_free(header);
+			fp = orig_fp;
+			goto free_addrs;
+		}
 	} else {
 		jit_data->header = header;
 		jit_data->ctx = jit;

arch/sparc/net/bpf_jit_comp_64.c

@@ -1602,7 +1602,11 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 	bpf_flush_icache(header, (u8 *)header + header->size);
 
 	if (!prog->is_func || extra_pass) {
-		bpf_jit_binary_lock_ro(header);
+		if (bpf_jit_binary_lock_ro(header)) {
+			bpf_jit_binary_free(header);
+			prog = orig_prog;
+			goto out_off;
+		}
 	} else {
 		jit_data->ctx = ctx;
 		jit_data->image = image_ptr;

arch/x86/net/bpf_jit_comp32.c

@@ -2600,8 +2600,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 	if (bpf_jit_enable > 1)
 		bpf_jit_dump(prog->len, proglen, pass + 1, image);
 
-	if (image) {
+	if (image && !bpf_jit_binary_lock_ro(header)) {
-		bpf_jit_binary_lock_ro(header);
 		prog->bpf_func = (void *)image;
 		prog->jited = 1;
 		prog->jited_len = proglen;

include/linux/filter.h

@@ -898,10 +898,11 @@ static inline int __must_check bpf_prog_lock_ro(struct bpf_prog *fp)
 	return 0;
 }
 
-static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr)
+static inline int __must_check
+bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr)
 {
 	set_vm_flush_reset_perms(hdr);
-	set_memory_rox((unsigned long)hdr, hdr->size >> PAGE_SHIFT);
+	return set_memory_rox((unsigned long)hdr, hdr->size >> PAGE_SHIFT);
 }
 
 int sk_filter_trim_cap(struct sock *sk, struct sk_buff *skb, unsigned int cap);