From 63c16c3a7608558a8e5ced96b8b6b06c490fd513 Mon Sep 17 00:00:00 2001 From: Chris Coulson Date: Wed, 23 Jan 2019 19:17:09 +0000 Subject: [PATCH] apparmor: Initial implementation of raw policy blob compression This adds an initial implementation of raw policy blob compression, using deflate. Compression level can be controlled via a new sysctl, "apparmor.rawdata_compression_level", which can be set to a value between 0 (no compression) and 9 (highest compression). Signed-off-by: Chris Coulson Signed-off-by: John Johansen --- security/apparmor/apparmorfs.c | 130 ++++++++++++++++++++++++++++-- security/apparmor/include/apparmor.h | 1 + security/apparmor/include/policy_unpack.h | 8 +- security/apparmor/lsm.c | 47 +++++++++++ security/apparmor/policy_unpack.c | 107 +++++++++++++++++++++++- 5 files changed, 285 insertions(+), 8 deletions(-) diff --git a/security/apparmor/apparmorfs.c b/security/apparmor/apparmorfs.c index fefee04..9c0e593 100644 --- a/security/apparmor/apparmorfs.c +++ b/security/apparmor/apparmorfs.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include @@ -68,6 +69,35 @@ * support fns */ +struct rawdata_f_data { + struct aa_loaddata *loaddata; +}; + +#define RAWDATA_F_DATA_BUF(p) (char *)(p + 1) + +static void rawdata_f_data_free(struct rawdata_f_data *private) +{ + if (!private) + return; + + aa_put_loaddata(private->loaddata); + kvfree(private); +} + +static struct rawdata_f_data *rawdata_f_data_alloc(size_t size) +{ + struct rawdata_f_data *ret; + + if (size > SIZE_MAX - sizeof(*ret)) + return ERR_PTR(-EINVAL); + + ret = kvzalloc(sizeof(*ret) + size, GFP_KERNEL); + if (!ret) + return ERR_PTR(-ENOMEM); + + return ret; +} + /** * aa_mangle_name - mangle a profile name to std profile layout form * @name: profile name to mangle (NOT NULL) @@ -1275,36 +1305,117 @@ static int seq_rawdata_hash_show(struct seq_file *seq, void *v) return 0; } +static int seq_rawdata_compressed_size_show(struct seq_file *seq, void *v) +{ + struct aa_loaddata *data = seq->private; + + seq_printf(seq, "%zu\n", data->compressed_size); + + return 0; +} + SEQ_RAWDATA_FOPS(abi); SEQ_RAWDATA_FOPS(revision); SEQ_RAWDATA_FOPS(hash); +SEQ_RAWDATA_FOPS(compressed_size); + +static int deflate_decompress(char *src, size_t slen, char *dst, size_t dlen) +{ + int error; + struct z_stream_s strm; + + if (aa_g_rawdata_compression_level == 0) { + if (dlen < slen) + return -EINVAL; + memcpy(dst, src, slen); + return 0; + } + + memset(&strm, 0, sizeof(strm)); + + strm.workspace = kvzalloc(zlib_inflate_workspacesize(), GFP_KERNEL); + if (!strm.workspace) + return -ENOMEM; + + strm.next_in = src; + strm.avail_in = slen; + + error = zlib_inflateInit(&strm); + if (error != Z_OK) { + error = -ENOMEM; + goto fail_inflate_init; + } + + strm.next_out = dst; + strm.avail_out = dlen; + + error = zlib_inflate(&strm, Z_FINISH); + if (error != Z_STREAM_END) + error = -EINVAL; + else + error = 0; + + zlib_inflateEnd(&strm); +fail_inflate_init: + kvfree(strm.workspace); + return error; +} static ssize_t rawdata_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) { - struct aa_loaddata *rawdata = file->private_data; + struct rawdata_f_data *private = file->private_data; - return simple_read_from_buffer(buf, size, ppos, rawdata->data, - rawdata->size); + return simple_read_from_buffer(buf, size, ppos, + RAWDATA_F_DATA_BUF(private), + private->loaddata->size); } static int rawdata_release(struct inode *inode, struct file *file) { - aa_put_loaddata(file->private_data); + rawdata_f_data_free(file->private_data); return 0; } static int rawdata_open(struct inode *inode, struct file *file) { + int error; + struct aa_loaddata *loaddata; + struct rawdata_f_data *private; + if (!policy_view_capable(NULL)) return -EACCES; - file->private_data = __aa_get_loaddata(inode->i_private); - if (!file->private_data) + + loaddata = __aa_get_loaddata(inode->i_private); + if (!loaddata) /* lost race: this entry is being reaped */ return -ENOENT; + private = rawdata_f_data_alloc(loaddata->size); + if (IS_ERR(private)) { + error = PTR_ERR(private); + goto fail_private_alloc; + } + + private->loaddata = loaddata; + + error = deflate_decompress(loaddata->data, loaddata->compressed_size, + RAWDATA_F_DATA_BUF(private), + loaddata->size); + if (error) + goto fail_decompress; + + file->private_data = private; return 0; + +fail_decompress: + rawdata_f_data_free(private); + return error; + +fail_private_alloc: + aa_put_loaddata(loaddata); + return error; } static const struct file_operations rawdata_fops = { @@ -1383,6 +1494,13 @@ int __aa_fs_create_rawdata(struct aa_ns *ns, struct aa_loaddata *rawdata) rawdata->dents[AAFS_LOADDATA_HASH] = dent; } + dent = aafs_create_file("compressed_size", S_IFREG | 0444, dir, + rawdata, + &seq_rawdata_compressed_size_fops); + if (IS_ERR(dent)) + goto fail; + rawdata->dents[AAFS_LOADDATA_COMPRESSED_SIZE] = dent; + dent = aafs_create_file("raw_data", S_IFREG | 0444, dir, rawdata, &rawdata_fops); if (IS_ERR(dent)) diff --git a/security/apparmor/include/apparmor.h b/security/apparmor/include/apparmor.h index 73d63b5..fc04e42 100644 --- a/security/apparmor/include/apparmor.h +++ b/security/apparmor/include/apparmor.h @@ -40,6 +40,7 @@ extern enum audit_mode aa_g_audit; extern bool aa_g_audit_header; extern bool aa_g_debug; extern bool aa_g_hash_policy; +extern int aa_g_rawdata_compression_level; extern bool aa_g_lock_policy; extern bool aa_g_logsyscall; extern bool aa_g_paranoid_load; diff --git a/security/apparmor/include/policy_unpack.h b/security/apparmor/include/policy_unpack.h index 8db4ab7..0739867 100644 --- a/security/apparmor/include/policy_unpack.h +++ b/security/apparmor/include/policy_unpack.h @@ -45,6 +45,7 @@ enum { AAFS_LOADDATA_REVISION, AAFS_LOADDATA_HASH, AAFS_LOADDATA_DATA, + AAFS_LOADDATA_COMPRESSED_SIZE, AAFS_LOADDATA_DIR, /* must be last actual entry */ AAFS_LOADDATA_NDENTS /* count of entries */ }; @@ -65,11 +66,16 @@ struct aa_loaddata { struct dentry *dents[AAFS_LOADDATA_NDENTS]; struct aa_ns *ns; char *name; - size_t size; + size_t size; /* the original size of the payload */ + size_t compressed_size; /* the compressed size of the payload */ long revision; /* the ns policy revision this caused */ int abi; unsigned char *hash; + /* Pointer to payload. If @compressed_size > 0, then this is the + * compressed version of the payload, else it is the uncompressed + * version (with the size indicated by @size). + */ char *data; }; diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c index 87500bd..5028467 100644 --- a/security/apparmor/lsm.c +++ b/security/apparmor/lsm.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include @@ -1266,6 +1267,16 @@ static const struct kernel_param_ops param_ops_aauint = { .get = param_get_aauint }; +static int param_set_aacompressionlevel(const char *val, + const struct kernel_param *kp); +static int param_get_aacompressionlevel(char *buffer, + const struct kernel_param *kp); +#define param_check_aacompressionlevel param_check_int +static const struct kernel_param_ops param_ops_aacompressionlevel = { + .set = param_set_aacompressionlevel, + .get = param_get_aacompressionlevel +}; + static int param_set_aalockpolicy(const char *val, const struct kernel_param *kp); static int param_get_aalockpolicy(char *buffer, const struct kernel_param *kp); #define param_check_aalockpolicy param_check_bool @@ -1296,6 +1307,11 @@ bool aa_g_hash_policy = IS_ENABLED(CONFIG_SECURITY_APPARMOR_HASH_DEFAULT); module_param_named(hash_policy, aa_g_hash_policy, aabool, S_IRUSR | S_IWUSR); #endif +/* policy loaddata compression level */ +int aa_g_rawdata_compression_level = Z_DEFAULT_COMPRESSION; +module_param_named(rawdata_compression_level, aa_g_rawdata_compression_level, + aacompressionlevel, 0400); + /* Debug mode */ bool aa_g_debug = IS_ENABLED(CONFIG_SECURITY_APPARMOR_DEBUG_MESSAGES); module_param_named(debug, aa_g_debug, aabool, S_IRUSR | S_IWUSR); @@ -1460,6 +1476,37 @@ static int param_get_aaintbool(char *buffer, const struct kernel_param *kp) return param_get_bool(buffer, &kp_local); } +static int param_set_aacompressionlevel(const char *val, + const struct kernel_param *kp) +{ + int error; + + if (!apparmor_enabled) + return -EINVAL; + if (apparmor_initialized) + return -EPERM; + + error = param_set_int(val, kp); + + aa_g_rawdata_compression_level = clamp(aa_g_rawdata_compression_level, + Z_NO_COMPRESSION, + Z_BEST_COMPRESSION); + pr_info("AppArmor: policy rawdata compression level set to %u\n", + aa_g_rawdata_compression_level); + + return error; +} + +static int param_get_aacompressionlevel(char *buffer, + const struct kernel_param *kp) +{ + if (!apparmor_enabled) + return -EINVAL; + if (apparmor_initialized && !policy_view_capable(NULL)) + return -EPERM; + return param_get_int(buffer, kp); +} + static int param_get_audit(char *buffer, const struct kernel_param *kp) { if (!apparmor_enabled) diff --git a/security/apparmor/policy_unpack.c b/security/apparmor/policy_unpack.c index f6c2bcb2..4c077aa 100644 --- a/security/apparmor/policy_unpack.c +++ b/security/apparmor/policy_unpack.c @@ -20,6 +20,7 @@ #include #include #include +#include #include "include/apparmor.h" #include "include/audit.h" @@ -143,9 +144,11 @@ bool aa_rawdata_eq(struct aa_loaddata *l, struct aa_loaddata *r) { if (l->size != r->size) return false; + if (l->compressed_size != r->compressed_size) + return false; if (aa_g_hash_policy && memcmp(l->hash, r->hash, aa_hash_size()) != 0) return false; - return memcmp(l->data, r->data, r->size) == 0; + return memcmp(l->data, r->data, r->compressed_size ?: r->size) == 0; } /* @@ -1012,6 +1015,105 @@ struct aa_load_ent *aa_load_ent_alloc(void) return ent; } +static int deflate_compress(const char *src, size_t slen, char **dst, + size_t *dlen) +{ + int error; + struct z_stream_s strm; + void *stgbuf, *dstbuf; + size_t stglen = deflateBound(slen); + + memset(&strm, 0, sizeof(strm)); + + if (stglen < slen) + return -EFBIG; + + strm.workspace = kvzalloc(zlib_deflate_workspacesize(MAX_WBITS, + MAX_MEM_LEVEL), + GFP_KERNEL); + if (!strm.workspace) + return -ENOMEM; + + error = zlib_deflateInit(&strm, aa_g_rawdata_compression_level); + if (error != Z_OK) { + error = -ENOMEM; + goto fail_deflate_init; + } + + stgbuf = kvzalloc(stglen, GFP_KERNEL); + if (!stgbuf) { + error = -ENOMEM; + goto fail_stg_alloc; + } + + strm.next_in = src; + strm.avail_in = slen; + strm.next_out = stgbuf; + strm.avail_out = stglen; + + error = zlib_deflate(&strm, Z_FINISH); + if (error != Z_STREAM_END) { + error = -EINVAL; + goto fail_deflate; + } + error = 0; + + if (is_vmalloc_addr(stgbuf)) { + dstbuf = kvzalloc(strm.total_out, GFP_KERNEL); + if (dstbuf) { + memcpy(dstbuf, stgbuf, strm.total_out); + vfree(stgbuf); + } + } else + /* + * If the staging buffer was kmalloc'd, then using krealloc is + * probably going to be faster. The destination buffer will + * always be smaller, so it's just shrunk, avoiding a memcpy + */ + dstbuf = krealloc(stgbuf, strm.total_out, GFP_KERNEL); + + if (!dstbuf) { + error = -ENOMEM; + goto fail_deflate; + } + + *dst = dstbuf; + *dlen = strm.total_out; + +fail_stg_alloc: + zlib_deflateEnd(&strm); +fail_deflate_init: + kvfree(strm.workspace); + return error; + +fail_deflate: + kvfree(stgbuf); + goto fail_stg_alloc; +} + +static int compress_loaddata(struct aa_loaddata *data) +{ + + AA_BUG(data->compressed_size > 0); + + /* + * Shortcut the no compression case, else we increase the amount of + * storage required by a small amount + */ + if (aa_g_rawdata_compression_level != 0) { + void *udata = data->data; + int error = deflate_compress(udata, data->size, &data->data, + &data->compressed_size); + if (error) + return error; + + kvfree(udata); + } else + data->compressed_size = data->size; + + return 0; +} + /** * aa_unpack - unpack packed binary profile(s) data loaded from user space * @udata: user data copied to kmem (NOT NULL) @@ -1080,6 +1182,9 @@ int aa_unpack(struct aa_loaddata *udata, struct list_head *lh, goto fail; } } + error = compress_loaddata(udata); + if (error) + goto fail; return 0; fail_profile: -- 2.7.4