Constify structures containing function pointers

The PaX team modified the kernel's modpost to report writeable function
pointers as section mismatches because they are potential exploit
targets. We could ignore the warnings, but their presence can obscure
actual issues. Proper const correctness can also catch programming
mistakes.

Building the kernel modules against a PaX/GrSecurity patched Linux 3.4.2
kernel reports 133 section mismatches prior to this patch. This patch
eliminates 130 of them. The quantity of writeable function pointers
eliminated by constifying each structure is as follows:

vdev_opts_t             52
zil_replay_func_t       24
zio_compress_info_t     24
zio_checksum_info_t     9
space_map_ops_t         7
arc_byteswap_func_t     5

The remaining 3 writeable function pointers cannot be addressed by this
patch. 2 of them are in zpl_fs_type. The kernel's sget function requires
that this be non-const. The final writeable function pointer is created
by SPL_SHRINKER_DECLARE. The kernel's set_shrinker() and
remove_shrinker() functions also require that this be non-const.

Signed-off-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1300
This commit is contained in:
Richard Yao 2013-02-14 23:37:43 -05:00 committed by Brian Behlendorf
parent c38367c73f
commit b01615d5ac
13 changed files with 59 additions and 59 deletions

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@ -1792,19 +1792,19 @@ ztest_replay_setattr(ztest_ds_t *zd, lr_setattr_t *lr, boolean_t byteswap)
return (0); return (0);
} }
zil_replay_func_t *ztest_replay_vector[TX_MAX_TYPE] = { zil_replay_func_t ztest_replay_vector[TX_MAX_TYPE] = {
NULL, /* 0 no such transaction type */ NULL, /* 0 no such transaction type */
(zil_replay_func_t *)ztest_replay_create, /* TX_CREATE */ (zil_replay_func_t)ztest_replay_create, /* TX_CREATE */
NULL, /* TX_MKDIR */ NULL, /* TX_MKDIR */
NULL, /* TX_MKXATTR */ NULL, /* TX_MKXATTR */
NULL, /* TX_SYMLINK */ NULL, /* TX_SYMLINK */
(zil_replay_func_t *)ztest_replay_remove, /* TX_REMOVE */ (zil_replay_func_t)ztest_replay_remove, /* TX_REMOVE */
NULL, /* TX_RMDIR */ NULL, /* TX_RMDIR */
NULL, /* TX_LINK */ NULL, /* TX_LINK */
NULL, /* TX_RENAME */ NULL, /* TX_RENAME */
(zil_replay_func_t *)ztest_replay_write, /* TX_WRITE */ (zil_replay_func_t)ztest_replay_write, /* TX_WRITE */
(zil_replay_func_t *)ztest_replay_truncate, /* TX_TRUNCATE */ (zil_replay_func_t)ztest_replay_truncate, /* TX_TRUNCATE */
(zil_replay_func_t *)ztest_replay_setattr, /* TX_SETATTR */ (zil_replay_func_t)ztest_replay_setattr, /* TX_SETATTR */
NULL, /* TX_ACL */ NULL, /* TX_ACL */
NULL, /* TX_CREATE_ACL */ NULL, /* TX_CREATE_ACL */
NULL, /* TX_CREATE_ATTR */ NULL, /* TX_CREATE_ATTR */

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@ -641,7 +641,7 @@ typedef struct dmu_object_info {
uint64_t doi_fill_count; /* number of non-empty blocks */ uint64_t doi_fill_count; /* number of non-empty blocks */
} dmu_object_info_t; } dmu_object_info_t;
typedef void arc_byteswap_func_t(void *buf, size_t size); typedef void (*const arc_byteswap_func_t)(void *buf, size_t size);
typedef struct dmu_object_type_info { typedef struct dmu_object_type_info {
dmu_object_byteswap_t ot_byteswap; dmu_object_byteswap_t ot_byteswap;
@ -649,8 +649,8 @@ typedef struct dmu_object_type_info {
char *ot_name; char *ot_name;
} dmu_object_type_info_t; } dmu_object_type_info_t;
typedef struct dmu_object_byteswap_info { typedef const struct dmu_object_byteswap_info {
arc_byteswap_func_t *ob_func; arc_byteswap_func_t ob_func;
char *ob_name; char *ob_name;
} dmu_object_byteswap_info_t; } dmu_object_byteswap_info_t;

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@ -33,7 +33,7 @@
extern "C" { extern "C" {
#endif #endif
typedef struct space_map_ops space_map_ops_t; typedef const struct space_map_ops space_map_ops_t;
typedef struct space_map { typedef struct space_map {
avl_tree_t sm_root; /* AVL tree of map segments */ avl_tree_t sm_root; /* AVL tree of map segments */

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@ -67,7 +67,7 @@ typedef void vdev_state_change_func_t(vdev_t *vd, int, int);
typedef void vdev_hold_func_t(vdev_t *vd); typedef void vdev_hold_func_t(vdev_t *vd);
typedef void vdev_rele_func_t(vdev_t *vd); typedef void vdev_rele_func_t(vdev_t *vd);
typedef struct vdev_ops { typedef const struct vdev_ops {
vdev_open_func_t *vdev_op_open; vdev_open_func_t *vdev_op_open;
vdev_close_func_t *vdev_op_close; vdev_close_func_t *vdev_op_close;
vdev_asize_func_t *vdev_op_asize; vdev_asize_func_t *vdev_op_asize;

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@ -371,7 +371,7 @@ extern void zfs_unmap_page(page_t *, caddr_t);
#endif /* HAVE_UIO_RW */ #endif /* HAVE_UIO_RW */
extern zil_get_data_t zfs_get_data; extern zil_get_data_t zfs_get_data;
extern zil_replay_func_t *zfs_replay_vector[TX_MAX_TYPE]; extern zil_replay_func_t zfs_replay_vector[TX_MAX_TYPE];
extern int zfsfstype; extern int zfsfstype;
#endif /* _KERNEL */ #endif /* _KERNEL */

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@ -436,7 +436,7 @@ typedef int zil_parse_blk_func_t(zilog_t *zilog, blkptr_t *bp, void *arg,
uint64_t txg); uint64_t txg);
typedef int zil_parse_lr_func_t(zilog_t *zilog, lr_t *lr, void *arg, typedef int zil_parse_lr_func_t(zilog_t *zilog, lr_t *lr, void *arg,
uint64_t txg); uint64_t txg);
typedef int zil_replay_func_t(void *, char *, boolean_t); typedef int (*const zil_replay_func_t)(void *, char *, boolean_t);
typedef int zil_get_data_t(void *arg, lr_write_t *lr, char *dbuf, zio_t *zio); typedef int zil_get_data_t(void *arg, lr_write_t *lr, char *dbuf, zio_t *zio);
extern int zil_parse(zilog_t *zilog, zil_parse_blk_func_t *parse_blk_func, extern int zil_parse(zilog_t *zilog, zil_parse_blk_func_t *parse_blk_func,
@ -452,7 +452,7 @@ extern zilog_t *zil_open(objset_t *os, zil_get_data_t *get_data);
extern void zil_close(zilog_t *zilog); extern void zil_close(zilog_t *zilog);
extern void zil_replay(objset_t *os, void *arg, extern void zil_replay(objset_t *os, void *arg,
zil_replay_func_t *replay_func[TX_MAX_TYPE]); zil_replay_func_t replay_func[TX_MAX_TYPE]);
extern boolean_t zil_replaying(zilog_t *zilog, dmu_tx_t *tx); extern boolean_t zil_replaying(zilog_t *zilog, dmu_tx_t *tx);
extern void zil_destroy(zilog_t *zilog, boolean_t keep_first); extern void zil_destroy(zilog_t *zilog, boolean_t keep_first);
extern void zil_destroy_sync(zilog_t *zilog, dmu_tx_t *tx); extern void zil_destroy_sync(zilog_t *zilog, dmu_tx_t *tx);

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@ -39,7 +39,7 @@ typedef void zio_checksum_t(const void *data, uint64_t size, zio_cksum_t *zcp);
/* /*
* Information about each checksum function. * Information about each checksum function.
*/ */
typedef struct zio_checksum_info { typedef const struct zio_checksum_info {
zio_checksum_t *ci_func[2]; /* checksum function for each byteorder */ zio_checksum_t *ci_func[2]; /* checksum function for each byteorder */
int ci_correctable; /* number of correctable bits */ int ci_correctable; /* number of correctable bits */
int ci_eck; /* uses zio embedded checksum? */ int ci_eck; /* uses zio embedded checksum? */

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@ -44,7 +44,7 @@ typedef int zio_decompress_func_t(void *src, void *dst,
/* /*
* Information about each compression function. * Information about each compression function.
*/ */
typedef struct zio_compress_info { typedef const struct zio_compress_info {
zio_compress_func_t *ci_compress; /* compression function */ zio_compress_func_t *ci_compress; /* compression function */
zio_decompress_func_t *ci_decompress; /* decompression function */ zio_decompress_func_t *ci_decompress; /* decompression function */
int ci_level; /* level parameter */ int ci_level; /* level parameter */

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@ -2802,10 +2802,10 @@ arc_read_done(zio_t *zio)
if (BP_SHOULD_BYTESWAP(zio->io_bp) && zio->io_error == 0) { if (BP_SHOULD_BYTESWAP(zio->io_bp) && zio->io_error == 0) {
dmu_object_byteswap_t bswap = dmu_object_byteswap_t bswap =
DMU_OT_BYTESWAP(BP_GET_TYPE(zio->io_bp)); DMU_OT_BYTESWAP(BP_GET_TYPE(zio->io_bp));
arc_byteswap_func_t *func = BP_GET_LEVEL(zio->io_bp) > 0 ? if (BP_GET_LEVEL(zio->io_bp) > 0)
byteswap_uint64_array : byteswap_uint64_array(buf->b_data, hdr->b_size);
dmu_ot_byteswap[bswap].ob_func; else
func(buf->b_data, hdr->b_size); dmu_ot_byteswap[bswap].ob_func(buf->b_data, hdr->b_size);
} }
arc_cksum_compute(buf, B_FALSE); arc_cksum_compute(buf, B_FALSE);

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@ -136,7 +136,7 @@ static int sa_modify_attrs(sa_handle_t *hdl, sa_attr_type_t newattr,
sa_data_op_t action, sa_data_locator_t *locator, void *datastart, sa_data_op_t action, sa_data_locator_t *locator, void *datastart,
uint16_t buflen, dmu_tx_t *tx); uint16_t buflen, dmu_tx_t *tx);
arc_byteswap_func_t *sa_bswap_table[] = { arc_byteswap_func_t sa_bswap_table[] = {
byteswap_uint64_array, byteswap_uint64_array,
byteswap_uint32_array, byteswap_uint32_array,
byteswap_uint16_array, byteswap_uint16_array,

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@ -910,26 +910,26 @@ zfs_replay_acl(zfs_sb_t *zsb, lr_acl_t *lr, boolean_t byteswap)
/* /*
* Callback vectors for replaying records * Callback vectors for replaying records
*/ */
zil_replay_func_t *zfs_replay_vector[TX_MAX_TYPE] = { zil_replay_func_t zfs_replay_vector[TX_MAX_TYPE] = {
(zil_replay_func_t *)zfs_replay_error, /* no such type */ (zil_replay_func_t)zfs_replay_error, /* no such type */
(zil_replay_func_t *)zfs_replay_create, /* TX_CREATE */ (zil_replay_func_t)zfs_replay_create, /* TX_CREATE */
(zil_replay_func_t *)zfs_replay_create, /* TX_MKDIR */ (zil_replay_func_t)zfs_replay_create, /* TX_MKDIR */
(zil_replay_func_t *)zfs_replay_create, /* TX_MKXATTR */ (zil_replay_func_t)zfs_replay_create, /* TX_MKXATTR */
(zil_replay_func_t *)zfs_replay_create, /* TX_SYMLINK */ (zil_replay_func_t)zfs_replay_create, /* TX_SYMLINK */
(zil_replay_func_t *)zfs_replay_remove, /* TX_REMOVE */ (zil_replay_func_t)zfs_replay_remove, /* TX_REMOVE */
(zil_replay_func_t *)zfs_replay_remove, /* TX_RMDIR */ (zil_replay_func_t)zfs_replay_remove, /* TX_RMDIR */
(zil_replay_func_t *)zfs_replay_link, /* TX_LINK */ (zil_replay_func_t)zfs_replay_link, /* TX_LINK */
(zil_replay_func_t *)zfs_replay_rename, /* TX_RENAME */ (zil_replay_func_t)zfs_replay_rename, /* TX_RENAME */
(zil_replay_func_t *)zfs_replay_write, /* TX_WRITE */ (zil_replay_func_t)zfs_replay_write, /* TX_WRITE */
(zil_replay_func_t *)zfs_replay_truncate, /* TX_TRUNCATE */ (zil_replay_func_t)zfs_replay_truncate, /* TX_TRUNCATE */
(zil_replay_func_t *)zfs_replay_setattr, /* TX_SETATTR */ (zil_replay_func_t)zfs_replay_setattr, /* TX_SETATTR */
(zil_replay_func_t *)zfs_replay_acl_v0, /* TX_ACL_V0 */ (zil_replay_func_t)zfs_replay_acl_v0, /* TX_ACL_V0 */
(zil_replay_func_t *)zfs_replay_acl, /* TX_ACL */ (zil_replay_func_t)zfs_replay_acl, /* TX_ACL */
(zil_replay_func_t *)zfs_replay_create_acl, /* TX_CREATE_ACL */ (zil_replay_func_t)zfs_replay_create_acl, /* TX_CREATE_ACL */
(zil_replay_func_t *)zfs_replay_create, /* TX_CREATE_ATTR */ (zil_replay_func_t)zfs_replay_create, /* TX_CREATE_ATTR */
(zil_replay_func_t *)zfs_replay_create_acl, /* TX_CREATE_ACL_ATTR */ (zil_replay_func_t)zfs_replay_create_acl, /* TX_CREATE_ACL_ATTR */
(zil_replay_func_t *)zfs_replay_create_acl, /* TX_MKDIR_ACL */ (zil_replay_func_t)zfs_replay_create_acl, /* TX_MKDIR_ACL */
(zil_replay_func_t *)zfs_replay_create, /* TX_MKDIR_ATTR */ (zil_replay_func_t)zfs_replay_create, /* TX_MKDIR_ATTR */
(zil_replay_func_t *)zfs_replay_create_acl, /* TX_MKDIR_ACL_ATTR */ (zil_replay_func_t)zfs_replay_create_acl, /* TX_MKDIR_ACL_ATTR */
(zil_replay_func_t *)zfs_replay_write2, /* TX_WRITE2 */ (zil_replay_func_t)zfs_replay_write2, /* TX_WRITE2 */
}; };

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@ -1956,7 +1956,7 @@ zil_resume(zilog_t *zilog)
} }
typedef struct zil_replay_arg { typedef struct zil_replay_arg {
zil_replay_func_t **zr_replay; zil_replay_func_t *zr_replay;
void *zr_arg; void *zr_arg;
boolean_t zr_byteswap; boolean_t zr_byteswap;
char *zr_lr; char *zr_lr;
@ -2075,7 +2075,7 @@ zil_incr_blks(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg)
* If this dataset has a non-empty intent log, replay it and destroy it. * If this dataset has a non-empty intent log, replay it and destroy it.
*/ */
void void
zil_replay(objset_t *os, void *arg, zil_replay_func_t *replay_func[TX_MAX_TYPE]) zil_replay(objset_t *os, void *arg, zil_replay_func_t replay_func[TX_MAX_TYPE])
{ {
zilog_t *zilog = dmu_objset_zil(os); zilog_t *zilog = dmu_objset_zil(os);
const zil_header_t *zh = zilog->zl_header; const zil_header_t *zh = zilog->zl_header;

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@ -453,20 +453,20 @@ zvol_replay_err(zvol_state_t *zv, lr_t *lr, boolean_t byteswap)
* Callback vectors for replaying records. * Callback vectors for replaying records.
* Only TX_WRITE is needed for zvol. * Only TX_WRITE is needed for zvol.
*/ */
zil_replay_func_t *zvol_replay_vector[TX_MAX_TYPE] = { zil_replay_func_t zvol_replay_vector[TX_MAX_TYPE] = {
(zil_replay_func_t *)zvol_replay_err, /* no such transaction type */ (zil_replay_func_t)zvol_replay_err, /* no such transaction type */
(zil_replay_func_t *)zvol_replay_err, /* TX_CREATE */ (zil_replay_func_t)zvol_replay_err, /* TX_CREATE */
(zil_replay_func_t *)zvol_replay_err, /* TX_MKDIR */ (zil_replay_func_t)zvol_replay_err, /* TX_MKDIR */
(zil_replay_func_t *)zvol_replay_err, /* TX_MKXATTR */ (zil_replay_func_t)zvol_replay_err, /* TX_MKXATTR */
(zil_replay_func_t *)zvol_replay_err, /* TX_SYMLINK */ (zil_replay_func_t)zvol_replay_err, /* TX_SYMLINK */
(zil_replay_func_t *)zvol_replay_err, /* TX_REMOVE */ (zil_replay_func_t)zvol_replay_err, /* TX_REMOVE */
(zil_replay_func_t *)zvol_replay_err, /* TX_RMDIR */ (zil_replay_func_t)zvol_replay_err, /* TX_RMDIR */
(zil_replay_func_t *)zvol_replay_err, /* TX_LINK */ (zil_replay_func_t)zvol_replay_err, /* TX_LINK */
(zil_replay_func_t *)zvol_replay_err, /* TX_RENAME */ (zil_replay_func_t)zvol_replay_err, /* TX_RENAME */
(zil_replay_func_t *)zvol_replay_write, /* TX_WRITE */ (zil_replay_func_t)zvol_replay_write, /* TX_WRITE */
(zil_replay_func_t *)zvol_replay_err, /* TX_TRUNCATE */ (zil_replay_func_t)zvol_replay_err, /* TX_TRUNCATE */
(zil_replay_func_t *)zvol_replay_err, /* TX_SETATTR */ (zil_replay_func_t)zvol_replay_err, /* TX_SETATTR */
(zil_replay_func_t *)zvol_replay_err, /* TX_ACL */ (zil_replay_func_t)zvol_replay_err, /* TX_ACL */
}; };
/* /*