From: Fabian Vogt Date: Wed, 10 Sep 2025 15:25:13 +0000 (+0200) Subject: riscv: kprobes: Fix probe address validation X-Git-Tag: v6.18-rc2~17^2~3 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=9e68bd803fac49274fde914466fd3b07c4d602c8;p=thirdparty%2Flinux.git riscv: kprobes: Fix probe address validation When adding a kprobe such as "p:probe/tcp_sendmsg _text+15392192", arch_check_kprobe would start iterating all instructions starting from _text until the probed address. Not only is this very inefficient, but literal values in there (e.g. left by function patching) are misinterpreted in a way that causes a desync. Fix this by doing it like x86: start the iteration at the closest preceding symbol instead of the given starting point. Fixes: 87f48c7ccc73 ("riscv: kprobe: Fixup kernel panic when probing an illegal position") Signed-off-by: Fabian Vogt Signed-off-by: Marvin Friedrich Acked-by: Guo Ren Link: https://lore.kernel.org/r/6191817.lOV4Wx5bFT@fvogt-thinkpad Signed-off-by: Paul Walmsley --- diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c index c0738d6c6498a..8723390c7cad5 100644 --- a/arch/riscv/kernel/probes/kprobes.c +++ b/arch/riscv/kernel/probes/kprobes.c @@ -49,10 +49,15 @@ static void __kprobes arch_simulate_insn(struct kprobe *p, struct pt_regs *regs) post_kprobe_handler(p, kcb, regs); } -static bool __kprobes arch_check_kprobe(struct kprobe *p) +static bool __kprobes arch_check_kprobe(unsigned long addr) { - unsigned long tmp = (unsigned long)p->addr - p->offset; - unsigned long addr = (unsigned long)p->addr; + unsigned long tmp, offset; + + /* start iterating at the closest preceding symbol */ + if (!kallsyms_lookup_size_offset(addr, NULL, &offset)) + return false; + + tmp = addr - offset; while (tmp <= addr) { if (tmp == addr) @@ -71,7 +76,7 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) if ((unsigned long)insn & 0x1) return -EILSEQ; - if (!arch_check_kprobe(p)) + if (!arch_check_kprobe((unsigned long)p->addr)) return -EILSEQ; /* copy instruction */