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authorRicardo Neri <ricardo.neri-calderon@linux.intel.com>2017-10-27 23:25:33 +0300
committerThomas Gleixner <tglx@linutronix.de>2017-11-01 23:50:09 +0300
commitb8d2eff3b1c6e46238a5fb3f56843e9974b4889f (patch)
tree47da69dfd06434956d5cc407790d527c1fd31e0b /arch/x86/mm
parentb15d70df6e685912be8bbcb7557d277d48aa942c (diff)
downloadlinux-b8d2eff3b1c6e46238a5fb3f56843e9974b4889f.tar.xz
x86/mpx: Use signed variables to compute effective addresses
Even though memory addresses are unsigned, the operands used to compute the effective address do have a sign. This is true for ModRM.rm, SIB.base, SIB.index as well as the displacement bytes. Thus, signed variables shall be used when computing the effective address from these operands. Once the signed effective address has been computed, it is casted to an unsigned long to determine the linear address. Variables are renamed to better reflect the type of address being computed. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: Adan Hawthorn <adanhawthorn@gmail.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Nathan Howard <liverlint@gmail.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Joe Perches <joe@perches.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Link: https://lkml.kernel.org/r/1509135945-13762-7-git-send-email-ricardo.neri-calderon@linux.intel.com
Diffstat (limited to 'arch/x86/mm')
-rw-r--r--arch/x86/mm/mpx.c20
1 files changed, 14 insertions, 6 deletions
diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c
index f4c48a01c906..57e5bf58ea34 100644
--- a/arch/x86/mm/mpx.c
+++ b/arch/x86/mm/mpx.c
@@ -138,8 +138,9 @@ static int get_reg_offset(struct insn *insn, struct pt_regs *regs,
*/
static void __user *mpx_get_addr_ref(struct insn *insn, struct pt_regs *regs)
{
- unsigned long addr = -1L, base, indx;
int addr_offset, base_offset, indx_offset;
+ unsigned long linear_addr = -1L;
+ long eff_addr, base, indx;
insn_byte_t sib;
insn_get_modrm(insn);
@@ -150,7 +151,8 @@ static void __user *mpx_get_addr_ref(struct insn *insn, struct pt_regs *regs)
addr_offset = get_reg_offset(insn, regs, REG_TYPE_RM);
if (addr_offset < 0)
goto out;
- addr = regs_get_register(regs, addr_offset);
+
+ eff_addr = regs_get_register(regs, addr_offset);
} else {
if (insn->sib.nbytes) {
base_offset = get_reg_offset(insn, regs, REG_TYPE_BASE);
@@ -163,17 +165,23 @@ static void __user *mpx_get_addr_ref(struct insn *insn, struct pt_regs *regs)
base = regs_get_register(regs, base_offset);
indx = regs_get_register(regs, indx_offset);
- addr = base + indx * (1 << X86_SIB_SCALE(sib));
+
+ eff_addr = base + indx * (1 << X86_SIB_SCALE(sib));
} else {
addr_offset = get_reg_offset(insn, regs, REG_TYPE_RM);
if (addr_offset < 0)
goto out;
- addr = regs_get_register(regs, addr_offset);
+
+ eff_addr = regs_get_register(regs, addr_offset);
}
- addr += insn->displacement.value;
+
+ eff_addr += insn->displacement.value;
}
+
+ linear_addr = (unsigned long)eff_addr;
+
out:
- return (void __user *)addr;
+ return (void __user *)linear_addr;
}
static int mpx_insn_decode(struct insn *insn,