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author | Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> | 2012-04-13 12:24:27 +0900 |
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committer | Ingo Molnar <mingo@kernel.org> | 2012-04-16 08:56:11 +0200 |
commit | 6c7b8e82aab75a25581c4d446fc87f96634e9ef9 (patch) | |
tree | 088f31f88c85a64304c171eced7b4233cbece6a9 /arch | |
parent | 7ea6411f4ceb62e5e53170d59d10996dca20c599 (diff) | |
download | lwn-6c7b8e82aab75a25581c4d446fc87f96634e9ef9.tar.gz lwn-6c7b8e82aab75a25581c4d446fc87f96634e9ef9.zip |
x86: Handle failures of parsing immediate operands in the instruction decoder
This can happen if the instruction is much longer than the maximum length,
or if insn->opnd_bytes is manually changed.
This patch also fixes warnings from -Wswitch-default flag.
Reported-by: Prashanth Nageshappa <prashanth@linux.vnet.ibm.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@linux.vnet.ibm.com>
Cc: Linux-mm <linux-mm@kvack.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Anton Arapov <anton@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: yrl.pp-manager.tt@hitachi.com
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120413032427.32577.42602.stgit@localhost.localdomain
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/x86/lib/insn.c | 53 |
1 files changed, 36 insertions, 17 deletions
diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c index 25feb1ae71c5..b1e6c4b2e8eb 100644 --- a/arch/x86/lib/insn.c +++ b/arch/x86/lib/insn.c @@ -379,8 +379,8 @@ err_out: return; } -/* Decode moffset16/32/64 */ -static void __get_moffset(struct insn *insn) +/* Decode moffset16/32/64. Return 0 if failed */ +static int __get_moffset(struct insn *insn) { switch (insn->addr_bytes) { case 2: @@ -397,15 +397,19 @@ static void __get_moffset(struct insn *insn) insn->moffset2.value = get_next(int, insn); insn->moffset2.nbytes = 4; break; + default: /* opnd_bytes must be modified manually */ + goto err_out; } insn->moffset1.got = insn->moffset2.got = 1; + return 1; + err_out: - return; + return 0; } -/* Decode imm v32(Iz) */ -static void __get_immv32(struct insn *insn) +/* Decode imm v32(Iz). Return 0 if failed */ +static int __get_immv32(struct insn *insn) { switch (insn->opnd_bytes) { case 2: @@ -417,14 +421,18 @@ static void __get_immv32(struct insn *insn) insn->immediate.value = get_next(int, insn); insn->immediate.nbytes = 4; break; + default: /* opnd_bytes must be modified manually */ + goto err_out; } + return 1; + err_out: - return; + return 0; } -/* Decode imm v64(Iv/Ov) */ -static void __get_immv(struct insn *insn) +/* Decode imm v64(Iv/Ov), Return 0 if failed */ +static int __get_immv(struct insn *insn) { switch (insn->opnd_bytes) { case 2: @@ -441,15 +449,18 @@ static void __get_immv(struct insn *insn) insn->immediate2.value = get_next(int, insn); insn->immediate2.nbytes = 4; break; + default: /* opnd_bytes must be modified manually */ + goto err_out; } insn->immediate1.got = insn->immediate2.got = 1; + return 1; err_out: - return; + return 0; } /* Decode ptr16:16/32(Ap) */ -static void __get_immptr(struct insn *insn) +static int __get_immptr(struct insn *insn) { switch (insn->opnd_bytes) { case 2: @@ -462,14 +473,17 @@ static void __get_immptr(struct insn *insn) break; case 8: /* ptr16:64 is not exist (no segment) */ - return; + return 0; + default: /* opnd_bytes must be modified manually */ + goto err_out; } insn->immediate2.value = get_next(unsigned short, insn); insn->immediate2.nbytes = 2; insn->immediate1.got = insn->immediate2.got = 1; + return 1; err_out: - return; + return 0; } /** @@ -489,7 +503,8 @@ void insn_get_immediate(struct insn *insn) insn_get_displacement(insn); if (inat_has_moffset(insn->attr)) { - __get_moffset(insn); + if (!__get_moffset(insn)) + goto err_out; goto done; } @@ -517,16 +532,20 @@ void insn_get_immediate(struct insn *insn) insn->immediate2.nbytes = 4; break; case INAT_IMM_PTR: - __get_immptr(insn); + if (!__get_immptr(insn)) + goto err_out; break; case INAT_IMM_VWORD32: - __get_immv32(insn); + if (!__get_immv32(insn)) + goto err_out; break; case INAT_IMM_VWORD: - __get_immv(insn); + if (!__get_immv(insn)) + goto err_out; break; default: - break; + /* Here, insn must have an immediate, but failed */ + goto err_out; } if (inat_has_second_immediate(insn->attr)) { insn->immediate2.value = get_next(char, insn); |