2.6.35.4-2: Fix x86_64 local root exploit

2 files changed, 229 insertions, 1 deletions

diff --git a/PATCHCFG b/PATCHCFG
index 5557bfb..2a93c11 100644
--- a/PATCHCFG
+++ b/PATCHCFG
@@ -15,13 +15,19 @@ PATCHES=(
          # add latest fixes from stable queue, if needed
          # http://git.kernel.org/?p=linux/kernel/git/stable/stable-queue.git
 
+         # Fix local root exploits
+         # http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff&h=c41d68a513c71e35a14f66d71782d27a79a81ea6
+         # http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=36d001c70d8a0144ac1d038f6876c484849a74de
+         # http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=eefdca043e8391dcd719711716492063030b55ac
+         compat-root-exploit.patch%1
+
          # add aufs2 support, in reference to:
          # http://aufs.sourceforge.net
          aufs2-base-20100802.patch%1
          aufs2-standalone-20100802.patch%1
         )
 # Name of the resulting patch (will be bzipped afterwards)
-PATCHNAME="patch-2.6.35.4-1-ARCH"
+PATCHNAME="patch-2.6.35.4-2-ARCH"
 
 # Run this before applying patches
 pre_apply() {
diff --git a/patches/compat-root-exploit.patch b/patches/compat-root-exploit.patch
new file mode 100644
index 0000000..d686595
--- /dev/null
+++ b/patches/compat-root-exploit.patch
@@ -0,0 +1,222 @@
+diff --git a/arch/ia64/include/asm/compat.h b/arch/ia64/include/asm/compat.h
+index f90edc8..9301a28 100644
+--- a/arch/ia64/include/asm/compat.h
++++ b/arch/ia64/include/asm/compat.h
+@@ -199,7 +199,7 @@ ptr_to_compat(void __user *uptr)
+ }
+ 
+ static __inline__ void __user *
+-compat_alloc_user_space (long len)
++arch_compat_alloc_user_space (long len)
+ {
+ 	struct pt_regs *regs = task_pt_regs(current);
+ 	return (void __user *) (((regs->r12 & 0xffffffff) & -16) - len);
+diff --git a/arch/mips/include/asm/compat.h b/arch/mips/include/asm/compat.h
+index 613f691..dbc5106 100644
+--- a/arch/mips/include/asm/compat.h
++++ b/arch/mips/include/asm/compat.h
+@@ -145,7 +145,7 @@ static inline compat_uptr_t ptr_to_compat(void __user *uptr)
+ 	return (u32)(unsigned long)uptr;
+ }
+ 
+-static inline void __user *compat_alloc_user_space(long len)
++static inline void __user *arch_compat_alloc_user_space(long len)
+ {
+ 	struct pt_regs *regs = (struct pt_regs *)
+ 		((unsigned long) current_thread_info() + THREAD_SIZE - 32) - 1;
+diff --git a/arch/parisc/include/asm/compat.h b/arch/parisc/include/asm/compat.h
+index 02b77ba..efa0b60 100644
+--- a/arch/parisc/include/asm/compat.h
++++ b/arch/parisc/include/asm/compat.h
+@@ -147,7 +147,7 @@ static inline compat_uptr_t ptr_to_compat(void __user *uptr)
+ 	return (u32)(unsigned long)uptr;
+ }
+ 
+-static __inline__ void __user *compat_alloc_user_space(long len)
++static __inline__ void __user *arch_compat_alloc_user_space(long len)
+ {
+ 	struct pt_regs *regs = &current->thread.regs;
+ 	return (void __user *)regs->gr[30];
+diff --git a/arch/powerpc/include/asm/compat.h b/arch/powerpc/include/asm/compat.h
+index 396d21a..a11d4ea 100644
+--- a/arch/powerpc/include/asm/compat.h
++++ b/arch/powerpc/include/asm/compat.h
+@@ -134,7 +134,7 @@ static inline compat_uptr_t ptr_to_compat(void __user *uptr)
+ 	return (u32)(unsigned long)uptr;
+ }
+ 
+-static inline void __user *compat_alloc_user_space(long len)
++static inline void __user *arch_compat_alloc_user_space(long len)
+ {
+ 	struct pt_regs *regs = current->thread.regs;
+ 	unsigned long usp = regs->gpr[1];
+diff --git a/arch/s390/include/asm/compat.h b/arch/s390/include/asm/compat.h
+index 104f200..a875c2f 100644
+--- a/arch/s390/include/asm/compat.h
++++ b/arch/s390/include/asm/compat.h
+@@ -181,7 +181,7 @@ static inline int is_compat_task(void)
+ 
+ #endif
+ 
+-static inline void __user *compat_alloc_user_space(long len)
++static inline void __user *arch_compat_alloc_user_space(long len)
+ {
+ 	unsigned long stack;
+ 
+diff --git a/arch/sparc/include/asm/compat.h b/arch/sparc/include/asm/compat.h
+index 5016f76..6f57325 100644
+--- a/arch/sparc/include/asm/compat.h
++++ b/arch/sparc/include/asm/compat.h
+@@ -167,7 +167,7 @@ static inline compat_uptr_t ptr_to_compat(void __user *uptr)
+ 	return (u32)(unsigned long)uptr;
+ }
+ 
+-static inline void __user *compat_alloc_user_space(long len)
++static inline void __user *arch_compat_alloc_user_space(long len)
+ {
+ 	struct pt_regs *regs = current_thread_info()->kregs;
+ 	unsigned long usp = regs->u_regs[UREG_I6];
+diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
+index e790bc1..4f5f71e 100644
+--- a/arch/x86/ia32/ia32entry.S
++++ b/arch/x86/ia32/ia32entry.S
+@@ -50,7 +50,12 @@
+ 	/*
+ 	 * Reload arg registers from stack in case ptrace changed them.
+ 	 * We don't reload %eax because syscall_trace_enter() returned
+-	 * the value it wants us to use in the table lookup.
++	 * the %rax value we should see.  Instead, we just truncate that
++	 * value to 32 bits again as we did on entry from user mode.
++	 * If it's a new value set by user_regset during entry tracing,
++	 * this matches the normal truncation of the user-mode value.
++	 * If it's -1 to make us punt the syscall, then (u32)-1 is still
++	 * an appropriately invalid value.
+ 	 */
+ 	.macro LOAD_ARGS32 offset, _r9=0
+ 	.if \_r9
+@@ -60,6 +65,7 @@
+ 	movl \offset+48(%rsp),%edx
+ 	movl \offset+56(%rsp),%esi
+ 	movl \offset+64(%rsp),%edi
++	movl %eax,%eax			/* zero extension */
+ 	.endm
+ 	
+ 	.macro CFI_STARTPROC32 simple
+@@ -153,7 +159,7 @@ ENTRY(ia32_sysenter_target)
+ 	testl  $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%r10)
+ 	CFI_REMEMBER_STATE
+ 	jnz  sysenter_tracesys
+-	cmpl	$(IA32_NR_syscalls-1),%eax
++	cmpq	$(IA32_NR_syscalls-1),%rax
+ 	ja	ia32_badsys
+ sysenter_do_call:
+ 	IA32_ARG_FIXUP
+@@ -195,7 +201,7 @@ sysexit_from_sys_call:
+ 	movl $AUDIT_ARCH_I386,%edi	/* 1st arg: audit arch */
+ 	call audit_syscall_entry
+ 	movl RAX-ARGOFFSET(%rsp),%eax	/* reload syscall number */
+-	cmpl $(IA32_NR_syscalls-1),%eax
++	cmpq $(IA32_NR_syscalls-1),%rax
+ 	ja ia32_badsys
+ 	movl %ebx,%edi			/* reload 1st syscall arg */
+ 	movl RCX-ARGOFFSET(%rsp),%esi	/* reload 2nd syscall arg */
+@@ -248,7 +254,7 @@ sysenter_tracesys:
+ 	call	syscall_trace_enter
+ 	LOAD_ARGS32 ARGOFFSET  /* reload args from stack in case ptrace changed it */
+ 	RESTORE_REST
+-	cmpl	$(IA32_NR_syscalls-1),%eax
++	cmpq	$(IA32_NR_syscalls-1),%rax
+ 	ja	int_ret_from_sys_call /* sysenter_tracesys has set RAX(%rsp) */
+ 	jmp	sysenter_do_call
+ 	CFI_ENDPROC
+@@ -314,7 +320,7 @@ ENTRY(ia32_cstar_target)
+ 	testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%r10)
+ 	CFI_REMEMBER_STATE
+ 	jnz   cstar_tracesys
+-	cmpl $IA32_NR_syscalls-1,%eax
++	cmpq $IA32_NR_syscalls-1,%rax
+ 	ja  ia32_badsys
+ cstar_do_call:
+ 	IA32_ARG_FIXUP 1
+@@ -367,7 +373,7 @@ cstar_tracesys:
+ 	LOAD_ARGS32 ARGOFFSET, 1  /* reload args from stack in case ptrace changed it */
+ 	RESTORE_REST
+ 	xchgl %ebp,%r9d
+-	cmpl $(IA32_NR_syscalls-1),%eax
++	cmpq $(IA32_NR_syscalls-1),%rax
+ 	ja int_ret_from_sys_call /* cstar_tracesys has set RAX(%rsp) */
+ 	jmp cstar_do_call
+ END(ia32_cstar_target)
+@@ -425,7 +431,7 @@ ENTRY(ia32_syscall)
+ 	orl   $TS_COMPAT,TI_status(%r10)
+ 	testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%r10)
+ 	jnz ia32_tracesys
+-	cmpl $(IA32_NR_syscalls-1),%eax
++	cmpq $(IA32_NR_syscalls-1),%rax
+ 	ja ia32_badsys
+ ia32_do_call:
+ 	IA32_ARG_FIXUP
+@@ -444,7 +450,7 @@ ia32_tracesys:
+ 	call syscall_trace_enter
+ 	LOAD_ARGS32 ARGOFFSET  /* reload args from stack in case ptrace changed it */
+ 	RESTORE_REST
+-	cmpl $(IA32_NR_syscalls-1),%eax
++	cmpq $(IA32_NR_syscalls-1),%rax
+ 	ja  int_ret_from_sys_call	/* ia32_tracesys has set RAX(%rsp) */
+ 	jmp ia32_do_call
+ END(ia32_syscall)
+diff --git a/arch/x86/include/asm/compat.h b/arch/x86/include/asm/compat.h
+index 306160e..1d9cd27 100644
+--- a/arch/x86/include/asm/compat.h
++++ b/arch/x86/include/asm/compat.h
+@@ -205,7 +205,7 @@ static inline compat_uptr_t ptr_to_compat(void __user *uptr)
+ 	return (u32)(unsigned long)uptr;
+ }
+ 
+-static inline void __user *compat_alloc_user_space(long len)
++static inline void __user *arch_compat_alloc_user_space(long len)
+ {
+ 	struct pt_regs *regs = task_pt_regs(current);
+ 	return (void __user *)regs->sp - len;
+diff --git a/include/linux/compat.h b/include/linux/compat.h
+index 168f7da..c766441 100644
+--- a/include/linux/compat.h
++++ b/include/linux/compat.h
+@@ -360,5 +360,8 @@ extern ssize_t compat_rw_copy_check_uvector(int type,
+ 		const struct compat_iovec __user *uvector, unsigned long nr_segs,
+ 		unsigned long fast_segs, struct iovec *fast_pointer,
+ 		struct iovec **ret_pointer);
++
++extern void __user *compat_alloc_user_space(unsigned long len);
++
+ #endif /* CONFIG_COMPAT */
+ #endif /* _LINUX_COMPAT_H */
+diff --git a/kernel/compat.c b/kernel/compat.c
+index 5adab05..91b33fb 100644
+--- a/kernel/compat.c
++++ b/kernel/compat.c
+@@ -1137,3 +1137,24 @@ compat_sys_sysinfo(struct compat_sysinfo __user *info)
+ 
+ 	return 0;
+ }
++
++/*
++ * Allocate user-space memory for the duration of a single system call,
++ * in order to marshall parameters inside a compat thunk.
++ */
++void __user *compat_alloc_user_space(unsigned long len)
++{
++	void __user *ptr;
++
++	/* If len would occupy more than half of the entire compat space... */
++	if (unlikely(len > (((compat_uptr_t)~0) >> 1)))
++		return NULL;
++
++	ptr = arch_compat_alloc_user_space(len);
++
++	if (unlikely(!access_ok(VERIFY_WRITE, ptr, len)))
++		return NULL;
++
++	return ptr;
++}
++EXPORT_SYMBOL_GPL(compat_alloc_user_space);