Commit-ID: 6c7b8e82aab75a25581c4d446fc87f96634e9ef9 Gitweb: http://git.kernel.org/tip/6c7b8e82aab75a25581c4d446fc87f96634e9ef9 Author: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx> AuthorDate: Fri, 13 Apr 2012 12:24:27 +0900 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Mon, 16 Apr 2012 08:56:11 +0200 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@xxxxxxxxxxxxxxxxxx> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxx> Cc: Jim Keniston <jkenisto@xxxxxxxxxxxxxxxxxx> Cc: Linux-mm <linux-mm@xxxxxxxxx> Cc: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Andi Kleen <andi@xxxxxxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxxxxx> Cc: Anton Arapov <anton@xxxxxxxxxx> Cc: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx> Cc: yrl.pp-manager.tt@xxxxxxxxxxx Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/20120413032427.32577.42602.stgit@localhost.localdomain Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- 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 25feb1a..b1e6c4b 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); -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>