From f497115d4cf8a430c5d9902ce35716ba5f9c21ef Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Mon, 21 May 2018 14:35:12 +1000 Subject: [PATCH] staging: lustre: simplify capability dropping. Lustre has a 'squash credentials' concept similar to the "anon_uid" for nfsd. When accessing a file with squashed credentials, we need to also drop capabilities. Linux has cap_drop_fs_set() and cap_drop_nfsd_set(). Rather than taking a completely different approach, this patch changes lustre to use this same cap_drop_*_set() approach. With this change we also drop CAP_MKNOD and CAP_MAC_OVERRIDE which are probably appropriate, and don't drop CAP_SYS_ADMIN or CAP_SYS_BOOT which should be irrelevant for file permission checking Calling both cap_drop_*_set() seems a bit clumsy, but gets the job done. Signed-off-by: NeilBrown Signed-off-by: Greg Kroah-Hartman --- drivers/staging/lustre/include/linux/libcfs/curproc.h | 10 ---------- drivers/staging/lustre/lustre/llite/file.c | 8 +++----- 2 files changed, 3 insertions(+), 15 deletions(-) diff --git a/drivers/staging/lustre/include/linux/libcfs/curproc.h b/drivers/staging/lustre/include/linux/libcfs/curproc.h index 83526f8..fc6f6eb 100644 --- a/drivers/staging/lustre/include/linux/libcfs/curproc.h +++ b/drivers/staging/lustre/include/linux/libcfs/curproc.h @@ -50,16 +50,6 @@ typedef u32 cfs_cap_t; -#define CFS_CAP_FS_MASK (BIT(CAP_CHOWN) | \ - BIT(CAP_DAC_OVERRIDE) | \ - BIT(CAP_DAC_READ_SEARCH) | \ - BIT(CAP_FOWNER) | \ - BIT(CAP_FSETID) | \ - BIT(CAP_LINUX_IMMUTABLE) | \ - BIT(CAP_SYS_ADMIN) | \ - BIT(CAP_SYS_BOOT) | \ - BIT(CAP_SYS_RESOURCE)) - static inline cfs_cap_t cfs_curproc_cap_pack(void) { /* cfs_cap_t is only the first word of kernel_cap_t */ diff --git a/drivers/staging/lustre/lustre/llite/file.c b/drivers/staging/lustre/lustre/llite/file.c index 0026fde..a77cadc 100644 --- a/drivers/staging/lustre/lustre/llite/file.c +++ b/drivers/staging/lustre/lustre/llite/file.c @@ -3050,7 +3050,6 @@ int ll_inode_permission(struct inode *inode, int mask) const struct cred *old_cred = NULL; struct cred *cred = NULL; bool squash_id = false; - cfs_cap_t cap; int rc = 0; if (mask & MAY_NOT_BLOCK) @@ -3094,10 +3093,9 @@ int ll_inode_permission(struct inode *inode, int mask) cred->fsuid = make_kuid(&init_user_ns, squash->rsi_uid); cred->fsgid = make_kgid(&init_user_ns, squash->rsi_gid); - for (cap = 0; cap < sizeof(cfs_cap_t) * 8; cap++) { - if ((1 << cap) & CFS_CAP_FS_MASK) - cap_lower(cred->cap_effective, cap); - } + cred->cap_effective = cap_drop_nfsd_set(cred->cap_effective); + cred->cap_effective = cap_drop_fs_set(cred->cap_effective); + old_cred = override_creds(cred); } -- 2.7.4