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authorRobin Murphy <robin.murphy@arm.com>2021-09-17 15:59:30 +0100
committerCatalin Marinas <catalin.marinas@arm.com>2021-09-21 14:50:19 +0100
commit59a68d4138086c015ab8241c3267eec5550fbd44 (patch)
tree833d1831affb5f492aceb9beaffe977d07d72b25 /arch/arm64
parent8c8a3b5bd960cd88f7655b5251dc28741e11f139 (diff)
arm64: Mitigate MTE issues with str{n}cmp()
As with strlen(), the patches importing the updated str{n}cmp() implementations were originally developed and tested before the advent of CONFIG_KASAN_HW_TAGS, and have subsequently revealed not to be MTE-safe. Since in-kernel MTE is still a rather niche case, let it temporarily fall back to the generic C versions for correctness until we can figure out the best fix. Fixes: 758602c04409 ("arm64: Import latest version of Cortex Strings' strcmp") Fixes: 020b199bc70d ("arm64: Import latest version of Cortex Strings' strncmp") Cc: <stable@vger.kernel.org> # 5.14.x Reported-by: Branislav Rankov <branislav.rankov@arm.com> Signed-off-by: Robin Murphy <robin.murphy@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/34dc4d12eec0adae49b0ac927df642ed10089d40.1631890770.git.robin.murphy@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64')
-rw-r--r--arch/arm64/include/asm/assembler.h5
-rw-r--r--arch/arm64/include/asm/string.h2
-rw-r--r--arch/arm64/lib/strcmp.S2
-rw-r--r--arch/arm64/lib/strncmp.S2
4 files changed, 9 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 89faca0e740d..bfa58409a4d4 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -525,6 +525,11 @@ alternative_endif
#define EXPORT_SYMBOL_NOKASAN(name) EXPORT_SYMBOL(name)
#endif
+#ifdef CONFIG_KASAN_HW_TAGS
+#define EXPORT_SYMBOL_NOHWKASAN(name)
+#else
+#define EXPORT_SYMBOL_NOHWKASAN(name) EXPORT_SYMBOL_NOKASAN(name)
+#endif
/*
* Emit a 64-bit absolute little endian symbol reference in a way that
* ensures that it will be resolved at build time, even when building a
diff --git a/arch/arm64/include/asm/string.h b/arch/arm64/include/asm/string.h
index 3a3264ff47b9..95f7686b728d 100644
--- a/arch/arm64/include/asm/string.h
+++ b/arch/arm64/include/asm/string.h
@@ -12,11 +12,13 @@ extern char *strrchr(const char *, int c);
#define __HAVE_ARCH_STRCHR
extern char *strchr(const char *, int c);
+#ifndef CONFIG_KASAN_HW_TAGS
#define __HAVE_ARCH_STRCMP
extern int strcmp(const char *, const char *);
#define __HAVE_ARCH_STRNCMP
extern int strncmp(const char *, const char *, __kernel_size_t);
+#endif
#define __HAVE_ARCH_STRLEN
extern __kernel_size_t strlen(const char *);
diff --git a/arch/arm64/lib/strcmp.S b/arch/arm64/lib/strcmp.S
index d7bee210a798..83bcad72ec97 100644
--- a/arch/arm64/lib/strcmp.S
+++ b/arch/arm64/lib/strcmp.S
@@ -173,4 +173,4 @@ L(done):
ret
SYM_FUNC_END_PI(strcmp)
-EXPORT_SYMBOL_NOKASAN(strcmp)
+EXPORT_SYMBOL_NOHWKASAN(strcmp)
diff --git a/arch/arm64/lib/strncmp.S b/arch/arm64/lib/strncmp.S
index 48d44f7fddb1..e42bcfcd37e6 100644
--- a/arch/arm64/lib/strncmp.S
+++ b/arch/arm64/lib/strncmp.S
@@ -258,4 +258,4 @@ L(ret0):
ret
SYM_FUNC_END_PI(strncmp)
-EXPORT_SYMBOL_NOKASAN(strncmp)
+EXPORT_SYMBOL_NOHWKASAN(strncmp)