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authorIan Abbott <abbotti@mev.co.uk>2019-04-24 15:14:11 +0100
committerMiklos Szeredi <mszeredi@redhat.com>2019-04-24 17:05:07 +0200
commit6407f44aaf2a39b5ccbb1cc1d342b906dcfa8a87 (patch)
tree62dec382d81a519220a349dbf42697cdec26966a /fs/fuse
parent29cc02d949b19fdeba9de9f54b2641005f5865c6 (diff)
downloadlinux-6407f44aaf2a39b5ccbb1cc1d342b906dcfa8a87.tar.bz2
fuse: Add ioctl flag for x32 compat ioctl
Currently, a CUSE server running on a 64-bit kernel can tell when an ioctl request comes from a process running a 32-bit ABI, but cannot tell whether the requesting process is using legacy IA32 emulation or x32 ABI. In particular, the server does not know the size of the client process's `time_t` type. For 64-bit kernels, the `FUSE_IOCTL_COMPAT` and `FUSE_IOCTL_32BIT` flags are currently set in the ioctl input request (`struct fuse_ioctl_in` member `flags`) for a 32-bit requesting process. This patch defines a new flag `FUSE_IOCTL_COMPAT_X32` and sets it if the 32-bit requesting process is using the x32 ABI. This allows the server process to distinguish between requests coming from client processes using IA32 emulation or the x32 ABI and so infer the size of the client process's `time_t` type and any other IA32/x32 differences. Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/fuse')
-rw-r--r--fs/fuse/file.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 1f9da7a5ad0d..3959f08279e6 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -2578,8 +2578,13 @@ long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
#if BITS_PER_LONG == 32
inarg.flags |= FUSE_IOCTL_32BIT;
#else
- if (flags & FUSE_IOCTL_COMPAT)
+ if (flags & FUSE_IOCTL_COMPAT) {
inarg.flags |= FUSE_IOCTL_32BIT;
+#ifdef CONFIG_X86_X32
+ if (in_x32_syscall())
+ inarg.flags |= FUSE_IOCTL_COMPAT_X32;
+#endif
+ }
#endif
/* assume all the iovs returned by client always fits in a page */