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Miller" , David Ahern , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: Christophe Leroy , bpf@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Kees Cook Subject: [PATCH bpf-next v2] bpf: Check return from set_memory_rox() and friends Date: Wed, 21 Feb 2024 15:45:19 +0100 Message-ID: <883c5a268483a89ab13ed630210328a926f16e5b.1708526584.git.christophe.leroy@csgroup.eu> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1708526720; l=7152; i=christophe.leroy@csgroup.eu; s=20211009; h=from:subject:message-id; bh=px5R6j4CfBD6L+NyH1bzxUD/SxQ6vZa1DBOK9wlHvDM=; b=5fyB6RbnqOSvhWk+nkpg1uqyuXjHfBWovHDcw9RzvTxBWVm802UGzWAm2DpZ2bZ9CHAAOxwGW 8Y4dIkxnweyCBz/O5h2TCcoI8fqwp689VQh4Vjvlh2ppNALjSkFKCaR X-Developer-Key: i=christophe.leroy@csgroup.eu; a=ed25519; pk=HIzTzUj91asvincQGOFx6+ZF5AoUuP9GdOtQChs7Mm0= X-Patchwork-Delegate: bpf@iogearbox.net arch_protect_bpf_trampoline() and alloc_new_pack() call set_memory_rox() which can fail, leading to unprotected memory. Take into account return from set_memory_XX() functions and add __must_check flag to arch_protect_bpf_trampoline(). Signed-off-by: Christophe Leroy Reviewed-by: Kees Cook --- v2: - Move list_add_tail(&pack->list, &pack_list) at the end of alloc_new_pack() - Split 2 lines that are reported longer than 80 chars by BPF patchwork's checkpatch report. --- arch/x86/net/bpf_jit_comp.c | 6 ++++-- include/linux/bpf.h | 4 ++-- kernel/bpf/bpf_struct_ops.c | 9 +++++++-- kernel/bpf/core.c | 29 ++++++++++++++++++++++------- kernel/bpf/trampoline.c | 18 ++++++++++++------ net/bpf/bpf_dummy_struct_ops.c | 4 +++- 6 files changed, 50 insertions(+), 20 deletions(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index e1390d1e331b..128c8ec9164e 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -2780,12 +2780,14 @@ void arch_free_bpf_trampoline(void *image, unsigned int size) bpf_prog_pack_free(image, size); } -void arch_protect_bpf_trampoline(void *image, unsigned int size) +int arch_protect_bpf_trampoline(void *image, unsigned int size) { + return 0; } -void arch_unprotect_bpf_trampoline(void *image, unsigned int size) +int arch_unprotect_bpf_trampoline(void *image, unsigned int size) { + return 0; } int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *image_end, diff --git a/include/linux/bpf.h b/include/linux/bpf.h index b86bd15a051d..bb2723c264df 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1116,8 +1116,8 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i void *func_addr); void *arch_alloc_bpf_trampoline(unsigned int size); void arch_free_bpf_trampoline(void *image, unsigned int size); -void arch_protect_bpf_trampoline(void *image, unsigned int size); -void arch_unprotect_bpf_trampoline(void *image, unsigned int size); +int __must_check arch_protect_bpf_trampoline(void *image, unsigned int size); +int arch_unprotect_bpf_trampoline(void *image, unsigned int size); int arch_bpf_trampoline_size(const struct btf_func_model *m, u32 flags, struct bpf_tramp_links *tlinks, void *func_addr); diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c index 0decd862dfe0..d920afb0dd60 100644 --- a/kernel/bpf/bpf_struct_ops.c +++ b/kernel/bpf/bpf_struct_ops.c @@ -488,7 +488,9 @@ static long bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key, if (err) goto reset_unlock; } - arch_protect_bpf_trampoline(st_map->image, PAGE_SIZE); + err = arch_protect_bpf_trampoline(st_map->image, PAGE_SIZE); + if (err) + goto reset_unlock; /* Let bpf_link handle registration & unregistration. * * Pair with smp_load_acquire() during lookup_elem(). @@ -497,7 +499,10 @@ static long bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key, goto unlock; } - arch_protect_bpf_trampoline(st_map->image, PAGE_SIZE); + err = arch_protect_bpf_trampoline(st_map->image, PAGE_SIZE); + if (err) + goto reset_unlock; + err = st_ops->reg(kdata); if (likely(!err)) { /* This refcnt increment on the map here after diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index c49619ef55d0..eb2256ba6daf 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -898,23 +898,31 @@ static LIST_HEAD(pack_list); static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns) { struct bpf_prog_pack *pack; + int err; pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)), GFP_KERNEL); if (!pack) return NULL; pack->ptr = bpf_jit_alloc_exec(BPF_PROG_PACK_SIZE); - if (!pack->ptr) { - kfree(pack); - return NULL; - } + if (!pack->ptr) + goto out; bpf_fill_ill_insns(pack->ptr, BPF_PROG_PACK_SIZE); bitmap_zero(pack->bitmap, BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE); - list_add_tail(&pack->list, &pack_list); set_vm_flush_reset_perms(pack->ptr); - set_memory_rox((unsigned long)pack->ptr, BPF_PROG_PACK_SIZE / PAGE_SIZE); + err = set_memory_rox((unsigned long)pack->ptr, + BPF_PROG_PACK_SIZE / PAGE_SIZE); + if (err) + goto out_free; + list_add_tail(&pack->list, &pack_list); return pack; + +out_free: + bpf_jit_free_exec(pack->ptr); +out: + kfree(pack); + return NULL; } void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns) @@ -929,9 +937,16 @@ void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns) size = round_up(size, PAGE_SIZE); ptr = bpf_jit_alloc_exec(size); if (ptr) { + int err; + bpf_fill_ill_insns(ptr, size); set_vm_flush_reset_perms(ptr); - set_memory_rox((unsigned long)ptr, size / PAGE_SIZE); + err = set_memory_rox((unsigned long)ptr, + size / PAGE_SIZE); + if (err) { + bpf_jit_free_exec(ptr); + ptr = NULL; + } } goto out; } diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index d382f5ebe06c..6e64ac9083b6 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -456,7 +456,9 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_direct_mut if (err < 0) goto out_free; - arch_protect_bpf_trampoline(im->image, im->size); + err = arch_protect_bpf_trampoline(im->image, im->size); + if (err) + goto out_free; WARN_ON(tr->cur_image && total == 0); if (tr->cur_image) @@ -1072,17 +1074,21 @@ void __weak arch_free_bpf_trampoline(void *image, unsigned int size) bpf_jit_free_exec(image); } -void __weak arch_protect_bpf_trampoline(void *image, unsigned int size) +int __weak arch_protect_bpf_trampoline(void *image, unsigned int size) { WARN_ON_ONCE(size > PAGE_SIZE); - set_memory_rox((long)image, 1); + return set_memory_rox((long)image, 1); } -void __weak arch_unprotect_bpf_trampoline(void *image, unsigned int size) +int __weak arch_unprotect_bpf_trampoline(void *image, unsigned int size) { + int err; WARN_ON_ONCE(size > PAGE_SIZE); - set_memory_nx((long)image, 1); - set_memory_rw((long)image, 1); + + err = set_memory_nx((long)image, 1); + if (err) + return err; + return set_memory_rw((long)image, 1); } int __weak arch_bpf_trampoline_size(const struct btf_func_model *m, u32 flags, diff --git a/net/bpf/bpf_dummy_struct_ops.c b/net/bpf/bpf_dummy_struct_ops.c index 02de71719aed..2aaecd8931fc 100644 --- a/net/bpf/bpf_dummy_struct_ops.c +++ b/net/bpf/bpf_dummy_struct_ops.c @@ -137,7 +137,9 @@ int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr, if (err < 0) goto out; - arch_protect_bpf_trampoline(image, PAGE_SIZE); + err = arch_protect_bpf_trampoline(image, PAGE_SIZE); + if (err) + goto out; prog_ret = dummy_ops_call_op(image, args); err = dummy_ops_copy_args(args);