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powerpc/bpf: Validate branch ranges

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upstream commit 3832ba4e283d7052b783dab8311df7e3590fed93

Add checks to ensure that we never emit branch instructions with
truncated branch offsets.

Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Tested-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/71d33a6b7603ec1013c9734dd8bdd4ff5e929142.1633464148.git.naveen.n.rao@linux.vnet.ibm.com
[drop ppc32 changes]
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Naveen N. Rao
2021-11-15 16:36:28 +05:30
committed by Greg Kroah-Hartman
parent 51cf71d5cb
commit 951fb7bf38
2 changed files with 26 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
arch/powerpc/net/bpf_jit.h
View File

@@ -12,6 +12,7 @@
#include <asm/types.h> #include <asm/types.h>
#include <asm/ppc-opcode.h> #include <asm/ppc-opcode.h>
#include <asm/code-patching.h>
#ifdef PPC64_ELF_ABI_v1 #ifdef PPC64_ELF_ABI_v1
#define FUNCTION_DESCR_SIZE 24 #define FUNCTION_DESCR_SIZE 24
@@ -24,13 +25,26 @@
#define EMIT(instr) PLANT_INSTR(image, ctx->idx, instr) #define EMIT(instr) PLANT_INSTR(image, ctx->idx, instr)
/* Long jump; (unconditional 'branch') */ /* Long jump; (unconditional 'branch') */
#define PPC_JMP(dest) EMIT(PPC_INST_BRANCH | \ #define PPC_JMP(dest) \
(((dest) - (ctx->idx * 4)) & 0x03fffffc)) do { \
long offset = (long)(dest) - (ctx->idx * 4); \
if (!is_offset_in_branch_range(offset)) { \
pr_err_ratelimited("Branch offset 0x%lx (@%u) out of range\n", offset, ctx->idx); \
return -ERANGE; \
} \
EMIT(PPC_INST_BRANCH | (offset & 0x03fffffc)); \
} while (0)
/* "cond" here covers BO:BI fields. */ /* "cond" here covers BO:BI fields. */
#define PPC_BCC_SHORT(cond, dest) EMIT(PPC_INST_BRANCH_COND | \ #define PPC_BCC_SHORT(cond, dest) \
(((cond) & 0x3ff) << 16) | \ do { \
(((dest) - (ctx->idx * 4)) & \ long offset = (long)(dest) - (ctx->idx * 4); \
0xfffc)) if (!is_offset_in_cond_branch_range(offset)) { \
pr_err_ratelimited("Conditional branch offset 0x%lx (@%u) out of range\n", offset, ctx->idx); \
return -ERANGE; \
} \
EMIT(PPC_INST_BRANCH_COND | (((cond) & 0x3ff) << 16) | (offset & 0xfffc)); \
} while (0)
/* Sign-extended 32-bit immediate load */ /* Sign-extended 32-bit immediate load */
#define PPC_LI32(d, i) do { \ #define PPC_LI32(d, i) do { \
if ((int)(uintptr_t)(i) >= -32768 && \ if ((int)(uintptr_t)(i) >= -32768 && \

8
arch/powerpc/net/bpf_jit_comp64.c
View File

@@ -224,7 +224,7 @@ static void bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx,
EMIT(PPC_RAW_BLRL()); EMIT(PPC_RAW_BLRL());
} }
static void bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 out) static int bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 out)
{ {
/* /*
* By now, the eBPF program has already setup parameters in r3, r4 and r5 * By now, the eBPF program has already setup parameters in r3, r4 and r5
@@ -285,7 +285,9 @@ static void bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32
bpf_jit_emit_common_epilogue(image, ctx); bpf_jit_emit_common_epilogue(image, ctx);
EMIT(PPC_RAW_BCTR()); EMIT(PPC_RAW_BCTR());
/* out: */ /* out: */
return 0;
} }
/* Assemble the body code between the prologue & epilogue */ /* Assemble the body code between the prologue & epilogue */
@@ -1010,7 +1012,9 @@ cond_branch:
*/ */
case BPF_JMP | BPF_TAIL_CALL: case BPF_JMP | BPF_TAIL_CALL:
ctx->seen |= SEEN_TAILCALL; ctx->seen |= SEEN_TAILCALL;
bpf_jit_emit_tail_call(image, ctx, addrs[i + 1]); ret = bpf_jit_emit_tail_call(image, ctx, addrs[i + 1]);
if (ret < 0)
return ret;
break; break;
default: default: