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authorLinus Torvalds <torvalds@linux-foundation.org>2019-11-21 12:15:24 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-11-21 12:15:24 -0800
commit81429eb8d9ca40b0c65bb739d29fa856c5d5e958 (patch)
tree9c41f66422a6334e3b31a19ff0b2785df2765a90
parentbe5fa3aac23fde1a00547ed87144e1f3268cdb48 (diff)
parente50be648aaa3da196d4f4ed49d1c5d4ec105fa4a (diff)
downloadlinux-stericsson-81429eb8d9ca40b0c65bb739d29fa856c5d5e958.tar.gz
Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fix from Will Deacon: "Ensure PAN is re-enabled following user fault in uaccess routines. After I thought we were done for 5.4, we had a report this week of a nasty issue that has been shown to leak data between different user address spaces thanks to corruption of entries in the TLB. In hindsight, we should have spotted this in review when the PAN code was merged back in v4.3, but hindsight is 20/20 and I'm trying not to beat myself up too much about it despite being fairly miserable. Anyway, the fix is "obvious" but the actual failure is more more subtle, and is described in the commit message. I've included a fairly mechanical follow-up patch here as well, which moves this checking out into the C wrappers which is what we do for {get,put}_user() already and allows us to remove these bloody assembly macros entirely. The patches have passed kernelci [1] [2] [3] and CKI [4] tests over night, as well as some targetted testing [5] for this particular issue. The first patch is tagged for stable and should be applied to 4.14, 4.19 and 5.3. I have separate backports for 4.4 and 4.9, which I'll send out once this has landed in your tree (although the original patch applies cleanly, it won't build for those two trees). Thanks to Pavel Tatashin for reporting this and Mark Rutland for helping to diagnose the issue and review/test the solution" * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: arm64: uaccess: Remove uaccess_*_not_uao asm macros arm64: uaccess: Ensure PAN is re-enabled after unhandled uaccess fault
-rw-r--r--arch/arm64/include/asm/asm-uaccess.h17
-rw-r--r--arch/arm64/include/asm/uaccess.h27
-rw-r--r--arch/arm64/lib/clear_user.S2
-rw-r--r--arch/arm64/lib/copy_from_user.S2
-rw-r--r--arch/arm64/lib/copy_in_user.S2
-rw-r--r--arch/arm64/lib/copy_to_user.S2
-rw-r--r--arch/arm64/lib/uaccess_flushcache.c6
7 files changed, 27 insertions, 31 deletions
diff --git a/arch/arm64/include/asm/asm-uaccess.h b/arch/arm64/include/asm/asm-uaccess.h
index 5bf963830b17..c764cc8fb3b6 100644
--- a/arch/arm64/include/asm/asm-uaccess.h
+++ b/arch/arm64/include/asm/asm-uaccess.h
@@ -59,23 +59,6 @@ alternative_else_nop_endif
#endif
/*
- * These macros are no-ops when UAO is present.
- */
- .macro uaccess_disable_not_uao, tmp1, tmp2
- uaccess_ttbr0_disable \tmp1, \tmp2
-alternative_if ARM64_ALT_PAN_NOT_UAO
- SET_PSTATE_PAN(1)
-alternative_else_nop_endif
- .endm
-
- .macro uaccess_enable_not_uao, tmp1, tmp2, tmp3
- uaccess_ttbr0_enable \tmp1, \tmp2, \tmp3
-alternative_if ARM64_ALT_PAN_NOT_UAO
- SET_PSTATE_PAN(0)
-alternative_else_nop_endif
- .endm
-
-/*
* Remove the address tag from a virtual address, if present.
*/
.macro untagged_addr, dst, addr
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index 097d6bfac0b7..127712b0b970 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -378,20 +378,34 @@ do { \
extern unsigned long __must_check __arch_copy_from_user(void *to, const void __user *from, unsigned long n);
#define raw_copy_from_user(to, from, n) \
({ \
- __arch_copy_from_user((to), __uaccess_mask_ptr(from), (n)); \
+ unsigned long __acfu_ret; \
+ uaccess_enable_not_uao(); \
+ __acfu_ret = __arch_copy_from_user((to), \
+ __uaccess_mask_ptr(from), (n)); \
+ uaccess_disable_not_uao(); \
+ __acfu_ret; \
})
extern unsigned long __must_check __arch_copy_to_user(void __user *to, const void *from, unsigned long n);
#define raw_copy_to_user(to, from, n) \
({ \
- __arch_copy_to_user(__uaccess_mask_ptr(to), (from), (n)); \
+ unsigned long __actu_ret; \
+ uaccess_enable_not_uao(); \
+ __actu_ret = __arch_copy_to_user(__uaccess_mask_ptr(to), \
+ (from), (n)); \
+ uaccess_disable_not_uao(); \
+ __actu_ret; \
})
extern unsigned long __must_check __arch_copy_in_user(void __user *to, const void __user *from, unsigned long n);
#define raw_copy_in_user(to, from, n) \
({ \
- __arch_copy_in_user(__uaccess_mask_ptr(to), \
- __uaccess_mask_ptr(from), (n)); \
+ unsigned long __aciu_ret; \
+ uaccess_enable_not_uao(); \
+ __aciu_ret = __arch_copy_in_user(__uaccess_mask_ptr(to), \
+ __uaccess_mask_ptr(from), (n)); \
+ uaccess_disable_not_uao(); \
+ __aciu_ret; \
})
#define INLINE_COPY_TO_USER
@@ -400,8 +414,11 @@ extern unsigned long __must_check __arch_copy_in_user(void __user *to, const voi
extern unsigned long __must_check __arch_clear_user(void __user *to, unsigned long n);
static inline unsigned long __must_check __clear_user(void __user *to, unsigned long n)
{
- if (access_ok(to, n))
+ if (access_ok(to, n)) {
+ uaccess_enable_not_uao();
n = __arch_clear_user(__uaccess_mask_ptr(to), n);
+ uaccess_disable_not_uao();
+ }
return n;
}
#define clear_user __clear_user
diff --git a/arch/arm64/lib/clear_user.S b/arch/arm64/lib/clear_user.S
index 10415572e82f..aeafc03e961a 100644
--- a/arch/arm64/lib/clear_user.S
+++ b/arch/arm64/lib/clear_user.S
@@ -20,7 +20,6 @@
* Alignment fixed up by hardware.
*/
ENTRY(__arch_clear_user)
- uaccess_enable_not_uao x2, x3, x4
mov x2, x1 // save the size for fixup return
subs x1, x1, #8
b.mi 2f
@@ -40,7 +39,6 @@ uao_user_alternative 9f, strh, sttrh, wzr, x0, 2
b.mi 5f
uao_user_alternative 9f, strb, sttrb, wzr, x0, 0
5: mov x0, #0
- uaccess_disable_not_uao x2, x3
ret
ENDPROC(__arch_clear_user)
EXPORT_SYMBOL(__arch_clear_user)
diff --git a/arch/arm64/lib/copy_from_user.S b/arch/arm64/lib/copy_from_user.S
index 680e74409ff9..ebb3c06cbb5d 100644
--- a/arch/arm64/lib/copy_from_user.S
+++ b/arch/arm64/lib/copy_from_user.S
@@ -54,10 +54,8 @@
end .req x5
ENTRY(__arch_copy_from_user)
- uaccess_enable_not_uao x3, x4, x5
add end, x0, x2
#include "copy_template.S"
- uaccess_disable_not_uao x3, x4
mov x0, #0 // Nothing to copy
ret
ENDPROC(__arch_copy_from_user)
diff --git a/arch/arm64/lib/copy_in_user.S b/arch/arm64/lib/copy_in_user.S
index 0bedae3f3792..3d8153a1ebce 100644
--- a/arch/arm64/lib/copy_in_user.S
+++ b/arch/arm64/lib/copy_in_user.S
@@ -56,10 +56,8 @@
end .req x5
ENTRY(__arch_copy_in_user)
- uaccess_enable_not_uao x3, x4, x5
add end, x0, x2
#include "copy_template.S"
- uaccess_disable_not_uao x3, x4
mov x0, #0
ret
ENDPROC(__arch_copy_in_user)
diff --git a/arch/arm64/lib/copy_to_user.S b/arch/arm64/lib/copy_to_user.S
index 2d88c736e8f2..357eae2c18eb 100644
--- a/arch/arm64/lib/copy_to_user.S
+++ b/arch/arm64/lib/copy_to_user.S
@@ -53,10 +53,8 @@
end .req x5
ENTRY(__arch_copy_to_user)
- uaccess_enable_not_uao x3, x4, x5
add end, x0, x2
#include "copy_template.S"
- uaccess_disable_not_uao x3, x4
mov x0, #0
ret
ENDPROC(__arch_copy_to_user)
diff --git a/arch/arm64/lib/uaccess_flushcache.c b/arch/arm64/lib/uaccess_flushcache.c
index cbfcbe6470a5..bfa30b75b2b8 100644
--- a/arch/arm64/lib/uaccess_flushcache.c
+++ b/arch/arm64/lib/uaccess_flushcache.c
@@ -28,7 +28,11 @@ void memcpy_page_flushcache(char *to, struct page *page, size_t offset,
unsigned long __copy_user_flushcache(void *to, const void __user *from,
unsigned long n)
{
- unsigned long rc = __arch_copy_from_user(to, from, n);
+ unsigned long rc;
+
+ uaccess_enable_not_uao();
+ rc = __arch_copy_from_user(to, from, n);
+ uaccess_disable_not_uao();
/* See above */
__clean_dcache_area_pop(to, n - rc);