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charset="utf-8" X-Mailer: b4 0.17-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=952; i=brauner@kernel.org; h=from:subject:message-id; bh=vNxDJDpmoyfXJahneUuQ9vEH9eL70g/8w71rNTJgUxc=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWS9zrsssUymaabA31Var5avOM5bfCJp4gvZaynZy78sz mbbvsPjXUcpC4MYF4OsmCKLQ7tJuNxynorNRpkaMHNYmUCGMHBxCsBEJKczMuyYrr82Yt6rR8wV ngvXr6z7d1Hu7s13rzfk5t00zdb9H3OckeGStmp/GZ/E1KSXmfqdfP1HWkLun/hu9/dXSsq18Bl 8+mwA X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Content-Transfer-Encoding: 8bit dasd_get_user_string() strips a trailing newline by looking at the last byte that was written. For an empty write that's the byte in front of the buffer it just allocated. Only look if something was written. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Christian Brauner (Amutable) --- drivers/s390/block/dasd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c index 2ffe404b890f..e97891e58957 100644 --- a/drivers/s390/block/dasd.c +++ b/drivers/s390/block/dasd.c @@ -933,7 +933,7 @@ char *dasd_get_user_string(const char __user *user_buf, size_t user_len) return ERR_PTR(-EFAULT); } /* got the string, now strip linefeed. */ - if (buffer[user_len - 1] == '\n') + if (user_len && buffer[user_len - 1] == '\n') buffer[user_len - 1] = 0; else buffer[user_len] = 0; -- 2.53.0