From cb1e922fa104bb0bb3aa5fc6ca7f7e070f3b55e9 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 28 Apr 2011 15:11:21 -0400 Subject: [PATCH 1/3] SELinux: pass last path component in may_create New inodes are created in a two stage process. We first will compute the label on a new inode in security_inode_create() and check if the operation is allowed. We will then actually re-compute that same label and apply it in security_inode_init_security(). The change to do new label calculations based in part on the last component of the path name only passed the path component information all the way down the security_inode_init_security hook. Down the security_inode_create hook the path information did not make it past may_create. Thus the two calculations came up differently and the permissions check might not actually be against the label that is created. Pass and use the same information in both places to harmonize the calculations and checks. Reported-by: Dominick Grift Signed-off-by: Eric Paris --- security/selinux/hooks.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index d52a9250741..9a93af81a0c 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -1573,7 +1573,8 @@ static int may_create(struct inode *dir, return rc; if (!newsid || !(sbsec->flags & SE_SBLABELSUPP)) { - rc = security_transition_sid(sid, dsec->sid, tclass, NULL, &newsid); + rc = security_transition_sid(sid, dsec->sid, tclass, + &dentry->d_name, &newsid); if (rc) return rc; } From 5d30b10bd68df007e7ae21e77d1e0ce184b53040 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 28 Apr 2011 15:55:52 -0400 Subject: [PATCH 2/3] flex_array: flex_array_prealloc takes a number of elements, not an end Change flex_array_prealloc to take the number of elements for which space should be allocated instead of the last (inclusive) element. Users and documentation are updated accordingly. flex_arrays got introduced before they had users. When folks started using it, they ended up needing a different API than was coded up originally. This swaps over to the API that folks apparently need. Based-on-patch-by: Steffen Klassert Signed-off-by: Eric Paris Tested-by: Chris Richards Acked-by: Dave Hansen Cc: stable@kernel.org [2.6.38+] --- Documentation/flexible-arrays.txt | 4 ++-- include/linux/flex_array.h | 2 +- lib/flex_array.c | 13 ++++++++----- security/selinux/ss/policydb.c | 6 +++--- 4 files changed, 14 insertions(+), 11 deletions(-) diff --git a/Documentation/flexible-arrays.txt b/Documentation/flexible-arrays.txt index cb8a3a00cc9..df904aec990 100644 --- a/Documentation/flexible-arrays.txt +++ b/Documentation/flexible-arrays.txt @@ -66,10 +66,10 @@ trick is to ensure that any needed memory allocations are done before entering atomic context, using: int flex_array_prealloc(struct flex_array *array, unsigned int start, - unsigned int end, gfp_t flags); + unsigned int nr_elements, gfp_t flags); This function will ensure that memory for the elements indexed in the range -defined by start and end has been allocated. Thereafter, a +defined by start and nr_elements has been allocated. Thereafter, a flex_array_put() call on an element in that range is guaranteed not to block. diff --git a/include/linux/flex_array.h b/include/linux/flex_array.h index 70e4efabe0f..ebeb2f3ad06 100644 --- a/include/linux/flex_array.h +++ b/include/linux/flex_array.h @@ -61,7 +61,7 @@ struct flex_array { struct flex_array *flex_array_alloc(int element_size, unsigned int total, gfp_t flags); int flex_array_prealloc(struct flex_array *fa, unsigned int start, - unsigned int end, gfp_t flags); + unsigned int nr_elements, gfp_t flags); void flex_array_free(struct flex_array *fa); void flex_array_free_parts(struct flex_array *fa); int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src, diff --git a/lib/flex_array.c b/lib/flex_array.c index c0ea40ba208..0c33b24498b 100644 --- a/lib/flex_array.c +++ b/lib/flex_array.c @@ -232,10 +232,10 @@ EXPORT_SYMBOL(flex_array_clear); /** * flex_array_prealloc - guarantee that array space exists - * @fa: the flex array for which to preallocate parts - * @start: index of first array element for which space is allocated - * @end: index of last (inclusive) element for which space is allocated - * @flags: page allocation flags + * @fa: the flex array for which to preallocate parts + * @start: index of first array element for which space is allocated + * @nr_elements: number of elements for which space is allocated + * @flags: page allocation flags * * This will guarantee that no future calls to flex_array_put() * will allocate memory. It can be used if you are expecting to @@ -245,13 +245,16 @@ EXPORT_SYMBOL(flex_array_clear); * Locking must be provided by the caller. */ int flex_array_prealloc(struct flex_array *fa, unsigned int start, - unsigned int end, gfp_t flags) + unsigned int nr_elements, gfp_t flags) { int start_part; int end_part; int part_nr; + unsigned int end; struct flex_array_part *part; + end = start + nr_elements - 1; + if (start >= fa->total_nr_elements || end >= fa->total_nr_elements) return -ENOSPC; if (elements_fit_in_base(fa)) diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c index e7b850ad57e..e6e7ce0d3d5 100644 --- a/security/selinux/ss/policydb.c +++ b/security/selinux/ss/policydb.c @@ -502,7 +502,7 @@ static int policydb_index(struct policydb *p) goto out; rc = flex_array_prealloc(p->type_val_to_struct_array, 0, - p->p_types.nprim - 1, GFP_KERNEL | __GFP_ZERO); + p->p_types.nprim, GFP_KERNEL | __GFP_ZERO); if (rc) goto out; @@ -519,7 +519,7 @@ static int policydb_index(struct policydb *p) goto out; rc = flex_array_prealloc(p->sym_val_to_name[i], - 0, p->symtab[i].nprim - 1, + 0, p->symtab[i].nprim, GFP_KERNEL | __GFP_ZERO); if (rc) goto out; @@ -2375,7 +2375,7 @@ int policydb_read(struct policydb *p, void *fp) goto bad; /* preallocate so we don't have to worry about the put ever failing */ - rc = flex_array_prealloc(p->type_attr_map_array, 0, p->p_types.nprim - 1, + rc = flex_array_prealloc(p->type_attr_map_array, 0, p->p_types.nprim, GFP_KERNEL | __GFP_ZERO); if (rc) goto bad; From bf69d41d198138e3c601e9a6645f4f1369aff7e0 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 28 Apr 2011 15:55:52 -0400 Subject: [PATCH 3/3] flex_arrays: allow zero length flex arrays Just like kmalloc will allow one to allocate a 0 length segment of memory flex arrays should do the same thing. It should bomb if you try to use something, but it should at least allow the allocation. This is needed because when SELinux switched to using flex_arrays in 2.6.38 the inability to allocate a 0 length array resulted in SELinux policy load returning -ENOSPC when previously it worked. Based-on-patch-by: Steffen Klassert Signed-off-by: Eric Paris Tested-by: Chris Richards Cc: stable@kernel.org [2.6.38+] --- lib/flex_array.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/lib/flex_array.c b/lib/flex_array.c index 0c33b24498b..854b57bd7d9 100644 --- a/lib/flex_array.c +++ b/lib/flex_array.c @@ -253,9 +253,16 @@ int flex_array_prealloc(struct flex_array *fa, unsigned int start, unsigned int end; struct flex_array_part *part; + if (!start && !nr_elements) + return 0; + if (start >= fa->total_nr_elements) + return -ENOSPC; + if (!nr_elements) + return 0; + end = start + nr_elements - 1; - if (start >= fa->total_nr_elements || end >= fa->total_nr_elements) + if (end >= fa->total_nr_elements) return -ENOSPC; if (elements_fit_in_base(fa)) return 0; @@ -346,6 +353,8 @@ int flex_array_shrink(struct flex_array *fa) int part_nr; int ret = 0; + if (!fa->total_nr_elements) + return 0; if (elements_fit_in_base(fa)) return ret; for (part_nr = 0; part_nr < FLEX_ARRAY_NR_BASE_PTRS; part_nr++) {