From 738cbe72adc5c8f2016c4c68aa5162631d4f27e1 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Mon, 8 Sep 2014 08:04:47 +0200 Subject: net: bpf: consolidate JIT binary allocator Introduced in commit 314beb9bcabf ("x86: bpf_jit_comp: secure bpf jit against spraying attacks") and later on replicated in aa2d2c73c21f ("s390/bpf,jit: address randomize and write protect jit code") for s390 architecture, write protection for BPF JIT images got added and a random start address of the JIT code, so that it's not on a page boundary anymore. Since both use a very similar allocator for the BPF binary header, we can consolidate this code into the BPF core as it's mostly JIT independant anyway. This will also allow for future archs that support DEBUG_SET_MODULE_RONX to just reuse instead of reimplementing it. JIT tested on x86_64 and s390x with BPF test suite. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Cc: Eric Dumazet Cc: Heiko Carstens Cc: Martin Schwidefsky Signed-off-by: David S. Miller --- include/linux/filter.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'include/linux') diff --git a/include/linux/filter.h b/include/linux/filter.h index 8f82ef3f1cdd..868764fcffb8 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -289,6 +289,11 @@ struct sock_fprog_kern { struct sock_filter *filter; }; +struct bpf_binary_header { + unsigned int pages; + u8 image[]; +}; + struct bpf_work_struct { struct bpf_prog *prog; struct work_struct work; @@ -358,6 +363,14 @@ struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, gfp_t gfp_extra_flags); void __bpf_prog_free(struct bpf_prog *fp); +typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size); + +struct bpf_binary_header * +bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, + unsigned int alignment, + bpf_jit_fill_hole_t bpf_fill_ill_insns); +void bpf_jit_binary_free(struct bpf_binary_header *hdr); + static inline void bpf_prog_unlock_free(struct bpf_prog *fp) { bpf_prog_unlock_ro(fp); -- cgit v1.2.3 From 286aad3c4014ca825c447e07e24f8929e6d266d2 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Mon, 8 Sep 2014 08:04:49 +0200 Subject: net: bpf: be friendly to kmemcheck Reported by Mikulas Patocka, kmemcheck currently barks out a false positive since we don't have special kmemcheck annotation for bitfields used in bpf_prog structure. We currently have jited:1, len:31 and thus when accessing len while CONFIG_KMEMCHECK enabled, kmemcheck throws a warning that we're reading uninitialized memory. As we don't need the whole bit universe for pages member, we can just split it to u16 and use a bool flag for jited instead of a bitfield. Signed-off-by: Mikulas Patocka Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- include/linux/filter.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include/linux') diff --git a/include/linux/filter.h b/include/linux/filter.h index 868764fcffb8..4b59edead908 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -300,9 +300,9 @@ struct bpf_work_struct { }; struct bpf_prog { - u32 pages; /* Number of allocated pages */ - u32 jited:1, /* Is our filter JIT'ed? */ - len:31; /* Number of filter blocks */ + u16 pages; /* Number of allocated pages */ + bool jited; /* Is our filter JIT'ed? */ + u32 len; /* Number of filter blocks */ struct sock_fprog_kern *orig_prog; /* Original BPF program */ struct bpf_work_struct *work; /* Deferred free work struct */ unsigned int (*bpf_func)(const struct sk_buff *skb, -- cgit v1.2.3