From: Kees Cook keescook@chromium.org
commit 95047b0519c17a28e09df5f38750f5354e3db4c4 upstream.
This refactors compression initialization slightly to better handle getting potentially called twice (via early pstore_register() calls and later pstore_init()) and improves the comments and reporting to be more verbose.
Signed-off-by: Kees Cook keescook@chromium.org Tested-by: Guenter Roeck groeck@chromium.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/pstore/platform.c | 48 +++++++++++++++++++++++++++++++++--------------- 1 file changed, 33 insertions(+), 15 deletions(-)
--- a/fs/pstore/platform.c +++ b/fs/pstore/platform.c @@ -274,36 +274,56 @@ static int pstore_decompress(void *in, v
static void allocate_buf_for_compression(void) { + struct crypto_comp *ctx; + int size; + char *buf; + + /* Skip if not built-in or compression backend not selected yet. */ if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !zbackend) return;
+ /* Skip if no pstore backend yet or compression init already done. */ + if (!psinfo || tfm) + return; + if (!crypto_has_comp(zbackend->name, 0, 0)) { - pr_err("No %s compression\n", zbackend->name); + pr_err("Unknown compression: %s\n", zbackend->name); return; }
- big_oops_buf_sz = zbackend->zbufsize(psinfo->bufsize); - if (big_oops_buf_sz <= 0) + size = zbackend->zbufsize(psinfo->bufsize); + if (size <= 0) { + pr_err("Invalid compression size for %s: %d\n", + zbackend->name, size); return; + }
- big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL); - if (!big_oops_buf) { - pr_err("allocate compression buffer error!\n"); + buf = kmalloc(size, GFP_KERNEL); + if (!buf) { + pr_err("Failed %d byte compression buffer allocation for: %s\n", + size, zbackend->name); return; }
- tfm = crypto_alloc_comp(zbackend->name, 0, 0); - if (IS_ERR_OR_NULL(tfm)) { - kfree(big_oops_buf); - big_oops_buf = NULL; - pr_err("crypto_alloc_comp() failed!\n"); + ctx = crypto_alloc_comp(zbackend->name, 0, 0); + if (IS_ERR_OR_NULL(ctx)) { + kfree(buf); + pr_err("crypto_alloc_comp('%s') failed: %ld\n", zbackend->name, + PTR_ERR(ctx)); return; } + + /* A non-NULL big_oops_buf indicates compression is available. */ + tfm = ctx; + big_oops_buf_sz = size; + big_oops_buf = buf; + + pr_info("Using compression: %s\n", zbackend->name); }
static void free_buf_for_compression(void) { - if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && !IS_ERR_OR_NULL(tfm)) + if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && tfm) crypto_free_comp(tfm); kfree(big_oops_buf); big_oops_buf = NULL; @@ -774,7 +794,6 @@ void __init pstore_choose_compression(vo for (step = zbackends; step->name; step++) { if (!strcmp(compress, step->name)) { zbackend = step; - pr_info("using %s compression\n", zbackend->name); return; } } @@ -791,8 +810,7 @@ static int __init pstore_init(void) * initialize compression because crypto was not ready. If so, * initialize compression now. */ - if (psinfo && !tfm) - allocate_buf_for_compression(); + allocate_buf_for_compression();
ret = pstore_init_fs(); if (ret)