linux-kernel - [PATCH 04/15] uprobes: install_breakpoint() should fail if is_swbp

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20120615154331.GA9578@redhat.com>
Date:	Fri, 15 Jun 2012 17:43:31 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	Anton Arapov <anton@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH 04/15] uprobes: install_breakpoint() should fail if
	is_swbp_insn() == T

install_breakpoint() returns -EEXIST if is_swbp_insn(orig_insn) == T,
the caller treats this code as success.

This is doubly wrong. The successful return should set UPROBE_COPY_INSN,
but the real problem is that it shouldn't succeed. If the probed insn is
int3 the application should get SIGTRAP, this won't happen with uprobe.

Probably we can fix this, we can add the UPROBE_SHARED_BP flag and teach
handle_swbp/set_orig_insn to handle this case correctly. But this needs
some complications and we have other insns which can't be probed, lets
make a simple fix for now.

I think this needs a cleanup. UPROBE_COPY_INSN should die, copy_insn()
should be called by alloc_uprobe(). arch_uprobe_analyze_insn() depends
on ->mm (ia32_compat) but it is called only once.

Signed-off-by: Oleg Nesterov <oleg@...hat.com>
Acked-by: Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
---
 kernel/events/uprobes.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 3ccdb29..ec78152 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -693,7 +693,7 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
 			return ret;

 		if (is_swbp_insn((uprobe_opcode_t *)uprobe->arch.insn))
-			return -EEXIST;
+			return -ENOTSUPP;

 		ret = arch_uprobe_analyze_insn(&uprobe->arch, mm, addr);
 		if (ret)
-- 
1.5.5.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/