pstore/ram: Fix bounds checks for mem_size, record_size, console_size and ftrace_size

The bounds check in ramoops_init_prz was incorrect and ramoops_init_przs
had no check. Additionally, ramoops_init_przs allows record_size to be 0,
but ramoops_pstore_write_buf would always crash in this case.

Signed-off-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>

1 files changed, 16 insertions, 2 deletions

diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 8741cea6253c..dba70e53b72c 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -189,7 +189,7 @@ static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
                                             struct pstore_info *psi)
 {
         struct ramoops_context *cxt = psi->data;
-        struct persistent_ram_zone *prz = cxt->przs[cxt->dump_write_cnt];
+        struct persistent_ram_zone *prz;
         size_t hlen;
 
         if (type == PSTORE_TYPE_CONSOLE) {
@@ -226,6 +226,11 @@ static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
         if (part != 1)
                 return -ENOSPC;
 
+        if (!cxt->przs)
+                return -ENOSPC;
+
+        prz = cxt->przs[cxt->dump_write_cnt];
+
         hlen = ramoops_write_kmsg_hdr(prz);
         if (size + hlen > prz->buffer_size)
                 size = prz->buffer_size - hlen;
@@ -297,6 +302,11 @@ static int __devinit ramoops_init_przs(struct device *dev,
         if (!cxt->record_size)
                 return 0;
 
+        if (*paddr + dump_mem_sz - cxt->phys_addr > cxt->size) {
+                dev_err(dev, "no room for dumps\n");
+                return -ENOMEM;
+        }
+
         cxt->max_dump_cnt = dump_mem_sz / cxt->record_size;
         if (!cxt->max_dump_cnt)
                 return -ENOMEM;
@@ -335,8 +345,12 @@ static int __devinit ramoops_init_prz(struct device *dev,
         if (!sz)
                 return 0;
 
-        if (*paddr + sz > *paddr + cxt->size)
+        if (*paddr + sz - cxt->phys_addr > cxt->size) {
+                dev_err(dev, "no room for mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
+                        sz, (unsigned long long)*paddr,
+                        cxt->size, (unsigned long long)cxt->phys_addr);
                 return -ENOMEM;
+        }
 
         *prz = persistent_ram_new(*paddr, sz, sig, cxt->ecc_size);
         if (IS_ERR(*prz)) {