[Xen-devel] [PATCH v2 01/20] livepatch: Bubble up sanity checks on Elf relocs

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

The checks for SHT_REL[,A] ELF sanity checks does not need to
be in the platform specific file and can be bubbled up
in the platform agnostic file.

This makes the ARM 32/64 implementation easier as the
duplicate checks don't have to be in the platform specific files.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>

---
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

v1: First submission
v2: Mirror checks for SHT_REL case.
---
 xen/arch/x86/livepatch.c   | 12 ------------
 xen/common/livepatch_elf.c | 17 +++++++++++++++++
 2 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/xen/arch/x86/livepatch.c b/xen/arch/x86/livepatch.c
index 952e897..5b0c863 100644
--- a/xen/arch/x86/livepatch.c
+++ b/xen/arch/x86/livepatch.c
@@ -146,18 +146,6 @@ int arch_livepatch_perform_rela(struct livepatch_elf *elf,
     uint64_t val;
     uint8_t *dest;
 
-    /* Nothing to do. */
-    if ( !rela->sec->sh_size )
-        return 0;
-
-    if ( rela->sec->sh_entsize < sizeof(Elf_RelA) ||
-         rela->sec->sh_size % rela->sec->sh_entsize )
-    {
-        dprintk(XENLOG_ERR, LIVEPATCH "%s: Section relative header is 
corrupted!\n",
-                elf->name);
-        return -EINVAL;
-    }
-
     for ( i = 0; i < (rela->sec->sh_size / rela->sec->sh_entsize); i++ )
     {
         r = rela->data + i * rela->sec->sh_entsize;
diff --git a/xen/common/livepatch_elf.c b/xen/common/livepatch_elf.c
index 789e8fc..cda9b27 100644
--- a/xen/common/livepatch_elf.c
+++ b/xen/common/livepatch_elf.c
@@ -335,6 +335,7 @@ int livepatch_elf_perform_relocs(struct livepatch_elf *elf)
     struct livepatch_elf_sec *r, *base;
     unsigned int i;
     int rc = 0;
+    size_t sz;
 
     ASSERT(elf->sym);
 
@@ -365,6 +366,22 @@ int livepatch_elf_perform_relocs(struct livepatch_elf *elf)
         }
 
         if ( r->sec->sh_type == SHT_RELA )
+            sz = sizeof(Elf_RelA);
+        else
+            sz = sizeof(Elf_Rel);
+
+        if ( !r->sec->sh_size )
+            continue;
+
+        if ( r->sec->sh_entsize < sz || r->sec->sh_size % r->sec->sh_entsize )
+        {
+            dprintk(XENLOG_ERR, LIVEPATCH "%s: Section relative header is 
corrupted!\n",
+                    elf->name);
+            rc = -EINVAL;
+            break;
+        }
+
+        if ( r->sec->sh_type == SHT_RELA )
             rc = arch_livepatch_perform_rela(elf, base, r);
         else /* SHT_REL */
             rc = arch_livepatch_perform_rel(elf, base, r);
-- 
2.4.11


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