[PATCH AUTOSEL 5.4 37/84] um: ubd: Prevent buffer overrun on command completion

[PATCH AUTOSEL 5.4 37/84] um: ubd: Prevent buffer overrun on command completion

[Sasha Levin]

From: Gabriel Krisman Bertazi <krisman@collabora.com>

[ Upstream commit 6e682d53fc1ef73a169e2a5300326cb23abb32ee ]

On the hypervisor side, when completing commands and the pipe is full,
we retry writing only the entries that failed, by offsetting
io_req_buffer, but we don't reduce the number of bytes written, which
can cause a buffer overrun of io_req_buffer, and write garbage to the
pipe.

Cc: Martyn Welch <martyn.welch@collabora.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/um/drivers/ubd_kern.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 6627d7c30f370..0f5d0a699a49b 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -1606,7 +1606,9 @@ int io_thread(void *arg)
 		written = 0;
 
 		do {
-			res = os_write_file(kernel_fd, ((char *) io_req_buffer) + written, n);
+			res = os_write_file(kernel_fd,
+					    ((char *) io_req_buffer) + written,
+					    n - written);
 			if (res >= 0) {
 				written += res;
 			}
-- 
2.20.1


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[PATCH AUTOSEL 5.4 67/84] um: falloc.h needs to be directly included for older libc

[Sasha Levin]

From: Alan Maguire <alan.maguire@oracle.com>

[ Upstream commit 35f3401317a3b26aa01fde8facfd320f2628fdcc ]

When building UML with glibc 2.17 installed, compilation
of arch/um/os-Linux/file.c fails due to failure to find
FALLOC_FL_PUNCH_HOLE and FALLOC_FL_KEEP_SIZE definitions.

It appears that /usr/include/bits/fcntl-linux.h (indirectly
included by /usr/include/fcntl.h) does not include falloc.h
with an older glibc, whereas a more up-to-date version
does.

Adding the direct include to file.c resolves the issue
and does not cause problems for more recent glibc.

Fixes: 50109b5a03b4 ("um: Add support for DISCARD in the UBD Driver")
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/um/os-Linux/file.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/um/os-Linux/file.c b/arch/um/os-Linux/file.c
index 5133e3afb96f7..3996937e2c0dd 100644
--- a/arch/um/os-Linux/file.c
+++ b/arch/um/os-Linux/file.c
@@ -8,6 +8,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <signal.h>
+#include <linux/falloc.h>
 #include <sys/ioctl.h>
 #include <sys/mount.h>
 #include <sys/socket.h>
-- 
2.20.1


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