From 9d876e79df6a2f364b9f2737eacd72ceb27da53a Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Tue, 21 Feb 2017 16:09:34 +0100 Subject: [PATCH] bpf: fix unlocking of jited image when module ronx not set Eric and Willem reported that they recently saw random crashes when JIT was in use and bisected this to 74451e66d516 ("bpf: make jited programs visible in traces"). Issue was that the consolidation part added bpf_jit_binary_unlock_ro() that would unlock previously made read-only memory back to read-write. However, DEBUG_SET_MODULE_RONX cannot be used for this to test for presence of set_memory_*() functions. We need to use ARCH_HAS_SET_MEMORY instead to fix this; also add the corresponding bpf_jit_binary_lock_ro() to filter.h. Fixes: 74451e66d516 ("bpf: make jited programs visible in traces") Reported-by: Eric Dumazet Reported-by: Willem de Bruijn Bisected-by: Eric Dumazet Signed-off-by: Daniel Borkmann Tested-by: Willem de Bruijn Signed-off-by: David S. Miller --- arch/arm64/net/bpf_jit_comp.c | 2 +- arch/s390/net/bpf_jit_comp.c | 2 +- arch/x86/net/bpf_jit_comp.c | 2 +- include/linux/filter.h | 13 +++++++++++-- 4 files changed, 14 insertions(+), 5 deletions(-) diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 05d12104d270a..a785554916c06 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -898,7 +898,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) bpf_flush_icache(header, ctx.image + ctx.idx); - set_memory_ro((unsigned long)header, header->pages); + bpf_jit_binary_lock_ro(header); prog->bpf_func = (void *)ctx.image; prog->jited = 1; diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index f1d0e62ec1dd5..b49c52a020871 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -1327,7 +1327,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) print_fn_code(jit.prg_buf, jit.size_prg); } if (jit.prg_buf) { - set_memory_ro((unsigned long)header, header->pages); + bpf_jit_binary_lock_ro(header); fp->bpf_func = (void *) jit.prg_buf; fp->jited = 1; } diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 18a62e2088262..32322ce9b4054 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -1165,7 +1165,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) if (image) { bpf_flush_icache(header, image + proglen); - set_memory_ro((unsigned long)header, header->pages); + bpf_jit_binary_lock_ro(header); prog->bpf_func = (void *)image; prog->jited = 1; } else { diff --git a/include/linux/filter.h b/include/linux/filter.h index 0c1cc9143cb23..0c167fdee5f7d 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -551,7 +551,7 @@ static inline bool bpf_prog_was_classic(const struct bpf_prog *prog) #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0])) -#ifdef CONFIG_DEBUG_SET_MODULE_RONX +#ifdef CONFIG_ARCH_HAS_SET_MEMORY static inline void bpf_prog_lock_ro(struct bpf_prog *fp) { set_memory_ro((unsigned long)fp, fp->pages); @@ -562,6 +562,11 @@ static inline void bpf_prog_unlock_ro(struct bpf_prog *fp) set_memory_rw((unsigned long)fp, fp->pages); } +static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr) +{ + set_memory_ro((unsigned long)hdr, hdr->pages); +} + static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr) { set_memory_rw((unsigned long)hdr, hdr->pages); @@ -575,10 +580,14 @@ static inline void bpf_prog_unlock_ro(struct bpf_prog *fp) { } +static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr) +{ +} + static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr) { } -#endif /* CONFIG_DEBUG_SET_MODULE_RONX */ +#endif /* CONFIG_ARCH_HAS_SET_MEMORY */ static inline struct bpf_binary_header * bpf_jit_binary_hdr(const struct bpf_prog *fp) -- 2.39.5