[PATCH bpf-next 2/2] bpf: Take return from set_memory_rox() into account with bpf_jit_binary_lock_ro()

Christophe Leroy
2024-02-18T10:55:30Z

set_memory_rox() can fail, leaving memory unprotected.

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

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
Previous patch introduces a dependency on this patch because it modifies bpf_prog_lock_ro(), but they are independant.
It is possible to apply this patch as standalone by handling trivial conflict with unmodified bpf_prog_lock_ro().
---
arch/arm/net/bpf_jit_32.c | 25 ++++++++++++-------------
arch/arm64/net/bpf_jit_comp.c | 21 +++++++++++++++------
arch/loongarch/net/bpf_jit.c | 21 +++++++++++++++------
arch/mips/net/bpf_jit_comp.c | 3 ++-
arch/parisc/net/bpf_jit_core.c | 8 +++++++-
arch/s390/net/bpf_jit_comp.c | 6 +++++-
arch/sparc/net/bpf_jit_comp_64.c | 6 +++++-
arch/x86/net/bpf_jit_comp32.c | 3 +--
include/linux/filter.h | 4 ++--
9 files changed, 64 insertions(+), 33 deletions(-)

diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
index 1d672457d02f..01516f83a95a 100644
--- a/arch/arm/net/bpf_jit_32.c
+++ b/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) {
- image_ptr = NULL;
- bpf_jit_binary_free(header);
- prog = orig_prog;
- goto out_imms;
- }
+ if (build_body(&ctx) < 0)
+ goto out_free;
build_epilogue(&ctx);

/* 3.) Extra pass to validate JITed Code */
- if (validate_code(&ctx)) {
- image_ptr = NULL;
- bpf_jit_binary_free(header);
- prog = orig_prog;
- goto out_imms;
- }
+ if (validate_code(&ctx))
+ goto out_free;
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;
}

diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index cfd5434de483..21a901d61aa1 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -1639,16 +1639,18 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
bpf_flush_icache(header, 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);
- prog->bpf_func = NULL;
- prog->jited = 0;
- prog->jited_len = 0;
- goto out_off;
+ goto out_free;
+ }
+ err = bpf_jit_binary_lock_ro(header);
+ if (err) {
+ 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;
@@ -1675,6 +1677,13 @@ 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:
+ bpf_jit_binary_free(header);
+ prog->bpf_func = NULL;
+ prog->jited = 0;
+ prog->jited_len = 0;
+ goto out_off;
}

bool bpf_jit_supports_kfunc_call(void)
diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c
index e73323d759d0..aafc5037fd2b 100644
--- a/arch/loongarch/net/bpf_jit.c
+++ b/arch/loongarch/net/bpf_jit.c
@@ -1294,16 +1294,18 @@ 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);
- prog->bpf_func = NULL;
- prog->jited = 0;
- prog->jited_len = 0;
- goto out_offset;
+ goto out_free;
+ }
+ err = bpf_jit_binary_lock_ro(header);
+ if (err) {
+ 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 +1336,13 @@ 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. */
diff --git a/arch/mips/net/bpf_jit_comp.c b/arch/mips/net/bpf_jit_comp.c
index a40d926b6513..e355dfca4400 100644
--- a/arch/mips/net/bpf_jit_comp.c
+++ b/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]);

diff --git a/arch/parisc/net/bpf_jit_core.c b/arch/parisc/net/bpf_jit_core.c
index d6ee2fd45550..979f45d4d1fb 100644
--- a/arch/parisc/net/bpf_jit_core.c
+++ b/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;
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index b418333bb086..e613eebfd349 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/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;
diff --git a/arch/sparc/net/bpf_jit_comp_64.c b/arch/sparc/net/bpf_jit_comp_64.c
index fa0759bfe498..73bf0aea8baf 100644
--- a/arch/sparc/net/bpf_jit_comp_64.c
+++ b/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;
diff --git a/arch/x86/net/bpf_jit_comp32.c b/arch/x86/net/bpf_jit_comp32.c
index b18ce19981ec..f2be1dcf3b24 100644
--- a/arch/x86/net/bpf_jit_comp32.c
+++ b/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) {
- bpf_jit_binary_lock_ro(header);
+ if (image && !bpf_jit_binary_lock_ro(header)) {
prog->bpf_func = (void *)image;
prog->jited = 1;
prog->jited_len = proglen;
diff --git a/include/linux/filter.h b/include/linux/filter.h
index fc0994dc5c72..314414fa6d70 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -892,10 +892,10 @@ 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);
--
2.43.0