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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
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26
arch/powerpc/net/bpf_jit.h
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@@ -12,6 +12,7 @@
#include <asm/types.h>
#include <asm/ppc-opcode.h>
#include <asm/code-patching.h>
#ifdef PPC64_ELF_ABI_v1
#define FUNCTION_DESCR_SIZE 24
@@ -24,13 +25,26 @@
#define EMIT(instr) PLANT_INSTR(image, ctx->idx, instr)
/* Long jump; (unconditional 'branch') */
#define PPC_JMP(dest) EMIT(PPC_INST_BRANCH | \
(((dest) - (ctx->idx * 4)) & 0x03fffffc))
#define PPC_JMP(dest) \
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. */
#define PPC_BCC_SHORT(cond, dest) EMIT(PPC_INST_BRANCH_COND | \
(((cond) & 0x3ff) << 16) | \
(((dest) - (ctx->idx * 4)) & \
0xfffc))
#define PPC_BCC_SHORT(cond, dest) \
do { \
long offset = (long)(dest) - (ctx->idx * 4); \
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 */
#define PPC_LI32(d, i) do { \
if ((int)(uintptr_t)(i) >= -32768 && \