bpf: Use vmalloc special flag

Use new flag VM_FLUSH_RESET_PERMS for handling freeing of special
permissioned memory in vmalloc and remove places where memory was set RW
before freeing which is no longer needed. Don't track if the memory is RO
anymore because it is now tracked in vmalloc.

Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-19-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/include/linux/filter.h b/include/linux/filter.h
index 14ec3bdad9a90ab67931e172d2d76c20a1d1cb18..7d3abde3f183cc2a96b88c89adaa72d7f90cc4af 100644 (file)
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -20,6 +20,7 @@
 #include <linux/set_memory.h>
 #include <linux/kallsyms.h>
 #include <linux/if_vlan.h>
+#include <linux/vmalloc.h>
 
 #include <net/sch_generic.h>
 
@@ -503,7 +504,6 @@ struct bpf_prog {
        u16                     pages;          /* Number of allocated pages */
        u16                     jited:1,        /* Is our filter JIT'ed? */
                                jit_requested:1,/* archs need to JIT the prog */
-                               undo_set_mem:1, /* Passed set_memory_ro() checkpoint */
                                gpl_compatible:1, /* Is filter GPL compatible? */
                                cb_access:1,    /* Is control block accessed? */
                                dst_needed:1,   /* Do we need dst entry? */
@@ -733,27 +733,17 @@ bpf_ctx_narrow_access_ok(u32 off, u32 size, u32 size_default)
 
 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
 {
-       fp->undo_set_mem = 1;
+       set_vm_flush_reset_perms(fp);
        set_memory_ro((unsigned long)fp, fp->pages);
 }
 
-static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
-{
-       if (fp->undo_set_mem)
-               set_memory_rw((unsigned long)fp, fp->pages);
-}
-
 static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr)
 {
+       set_vm_flush_reset_perms(hdr);
        set_memory_ro((unsigned long)hdr, hdr->pages);
        set_memory_x((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);
-}
-
 static inline struct bpf_binary_header *
 bpf_jit_binary_hdr(const struct bpf_prog *fp)
 {
@@ -789,7 +779,6 @@ void __bpf_prog_free(struct bpf_prog *fp);
 
 static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
 {
-       bpf_prog_unlock_ro(fp);
        __bpf_prog_free(fp);
 }
 

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index ff09d32a8a1be210e88a0e6f7f14596ee6b89f06..c605397c79f03050a22fa0e03b170e5c6a55f5a6 100644 (file)
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -848,7 +848,6 @@ void __weak bpf_jit_free(struct bpf_prog *fp)
        if (fp->jited) {
                struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp);
 
-               bpf_jit_binary_unlock_ro(hdr);
                bpf_jit_binary_free(hdr);
 
                WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));