From: Ard Biesheuvel <ard.biesheuvel@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: mark.rutland@arm.com, guillaume.gardet@arm.com,
marc.zyngier@arm.com, will.deacon@arm.com, james.morse@arm.com,
Ard Biesheuvel <ard.biesheuvel@arm.com>
Subject: [PATCH] arm64/module: deal with ambiguity in PRELxx relocation ranges
Date: Tue, 21 May 2019 13:57:07 +0100 [thread overview]
Message-ID: <20190521125707.6115-1-ard.biesheuvel@arm.com> (raw)
The R_AARCH64_PREL16 and R_AARCH64_PREL32 relocations are
documented as permitting a range of [-2^15 .. 2^16), resp.
[-2^31 .. 2^32). It is also documented that this means we
cannot detect overflow in some cases, which is bad.
Since we always interpret the targets of these relocations as
signed quantities (e.g., in the ksymtab handling code), let's
tighten the overflow checks so that targets that are out of
range for our signed interpretation of the relocated quantity
get flagged.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
---
arch/arm64/kernel/module.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kernel/module.c b/arch/arm64/kernel/module.c
index f713e2fc4d75..2e4e3915b4d0 100644
--- a/arch/arm64/kernel/module.c
+++ b/arch/arm64/kernel/module.c
@@ -99,12 +99,12 @@ static int reloc_data(enum aarch64_reloc_op op, void *place, u64 val, int len)
switch (len) {
case 16:
*(s16 *)place = sval;
- if (sval < S16_MIN || sval > U16_MAX)
+ if (sval < S16_MIN || sval > S16_MAX)
return -ERANGE;
break;
case 32:
*(s32 *)place = sval;
- if (sval < S32_MIN || sval > U32_MAX)
+ if (sval < S32_MIN || sval > S32_MAX)
return -ERANGE;
break;
case 64:
--
2.17.1
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next reply other threads:[~2019-05-21 12:57 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-21 12:57 Ard Biesheuvel [this message]
2019-05-23 10:24 ` [PATCH] arm64/module: deal with ambiguity in PRELxx relocation ranges Will Deacon
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