linux-kernel - [PATCH 2/6] binfmt_elf: open code copy_siginfo_to

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Message-Id: <20200406120312.1150405-3-hch@lst.de>
Date:   Mon,  6 Apr 2020 14:03:08 +0200
From:   Christoph Hellwig <hch@....de>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Alexander Viro <viro@...iv.linux.org.uk>
Cc:     Jeremy Kerr <jk@...abs.org>, Arnd Bergmann <arnd@...db.de>,
        linuxppc-dev@...ts.ozlabs.org, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 2/6] binfmt_elf: open code copy_siginfo_to_user to kernelspace buffer

Instead of messing with the address limit just open code the trivial
memcpy + memset logic.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 fs/binfmt_elf.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index f4713ea76e82..d744ce9a4b52 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1556,10 +1556,9 @@ static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm)
 static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata,
 		const kernel_siginfo_t *siginfo)
 {
-	mm_segment_t old_fs = get_fs();
-	set_fs(KERNEL_DS);
-	copy_siginfo_to_user((user_siginfo_t __user *) csigdata, siginfo);
-	set_fs(old_fs);
+	memcpy(csigdata, siginfo, sizeof(struct kernel_siginfo));
+	memset((char *)csigdata + sizeof(struct kernel_siginfo), 0,
+		SI_EXPANSION_SIZE);
 	fill_note(note, "CORE", NT_SIGINFO, sizeof(*csigdata), csigdata);
 }
 
-- 
2.25.1