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authorMichael Ellerman <michael@ellerman.id.au>2005-11-03 21:10:48 +1100
committerMichael Ellerman <michael@ellerman.id.au>2005-11-04 12:10:51 +1100
commit30415f6a63f3383a18e9adf7c144acabe6893f63 (patch)
tree1243fd078c52fca858145d5b96e6e4a2d310de4e
parentb8f510219edc719d4c305918e16edc578bcfc16f (diff)
powerpc: Fix random memory corruption in merged elf.h
The merged verison of ELF_CORE_COPY_REGS is basically the PPC64 version, with a memset that came from PPC and a few types abstracted out into #defines. But it's not _quite_ right. The first problem is we calculate the number of registers with: nregs = sizeof(struct pt_regs) / sizeof(ELF_GREG_TYPE) For a 32-bit process on a 64-bit kernel that's bogus because the registers are 64 bits, but ELF_GREG_TYPE is u32, so nregs == 88 which is wrong. The other problem is the memset, which assumes a struct pt_regs is smaller than a struct elf_regs. For a 32-bit process on a 64-bit kernel that's false. The fix is to calculate the number of regs using sizeof(unsigned long), which should always be right, and just memset the whole damn thing _before_ copying the registers in. Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
-rw-r--r--include/asm-powerpc/elf.h22
1 files changed, 13 insertions, 9 deletions
diff --git a/include/asm-powerpc/elf.h b/include/asm-powerpc/elf.h
index d22b10021b5d..d140577d0a05 100644
--- a/include/asm-powerpc/elf.h
+++ b/include/asm-powerpc/elf.h
@@ -178,18 +178,22 @@ typedef elf_vrreg_t elf_vrregset_t32[ELF_NVRREG32];
static inline void ppc_elf_core_copy_regs(elf_gregset_t elf_regs,
struct pt_regs *regs)
{
- int i;
- int gprs = sizeof(struct pt_regs)/sizeof(ELF_GREG_TYPE);
+ int i, nregs;
- if (gprs > ELF_NGREG)
- gprs = ELF_NGREG;
+ memset((void *)elf_regs, 0, sizeof(elf_gregset_t));
- for (i=0; i < gprs; i++)
- elf_regs[i] = (elf_greg_t)((ELF_GREG_TYPE *)regs)[i];
-
- memset((char *)(elf_regs) + sizeof(struct pt_regs), 0, \
- sizeof(elf_gregset_t) - sizeof(struct pt_regs));
+ /* Our registers are always unsigned longs, whether we're a 32 bit
+ * process or 64 bit, on either a 64 bit or 32 bit kernel.
+ * Don't use ELF_GREG_TYPE here. */
+ nregs = sizeof(struct pt_regs) / sizeof(unsigned long);
+ if (nregs > ELF_NGREG)
+ nregs = ELF_NGREG;
+ for (i = 0; i < nregs; i++) {
+ /* This will correctly truncate 64 bit registers to 32 bits
+ * for a 32 bit process on a 64 bit kernel. */
+ elf_regs[i] = (elf_greg_t)((ELF_GREG_TYPE *)regs)[i];
+ }
}
#define ELF_CORE_COPY_REGS(gregs, regs) ppc_elf_core_copy_regs(gregs, regs);