contrib/elf2dmp: Always check for PA resolution failure

Not checking PA resolution failure can result in NULL deference.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Tested-by: Viktor Prutyanov <viktor.prutyanov@phystech.edu>
Message-id: 20240307-elf2dmp-v4-10-4f324ad4d99d@daynix.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

contrib/elf2dmp/addrspace.c

@@ -22,7 +22,7 @@ static struct pa_block *pa_space_find_block(struct pa_space *ps, uint64_t pa)
     return NULL;
 }
 
-static uint8_t *pa_space_resolve(struct pa_space *ps, uint64_t pa)
+static void *pa_space_resolve(struct pa_space *ps, uint64_t pa)
 {
     struct pa_block *block = pa_space_find_block(ps, pa);
 
@@ -33,6 +33,19 @@ static uint8_t *pa_space_resolve(struct pa_space *ps, uint64_t pa)
     return block->addr + (pa - block->paddr);
 }
 
+static bool pa_space_read64(struct pa_space *ps, uint64_t pa, uint64_t *value)
+{
+    uint64_t *resolved = pa_space_resolve(ps, pa);
+
+    if (!resolved) {
+        return false;
+    }
+
+    *value = *resolved;
+
+    return true;
+}
+
 static void pa_block_align(struct pa_block *b)
 {
     uint64_t low_align = ((b->paddr - 1) | ELF2DMP_PAGE_MASK) + 1 - b->paddr;
@@ -106,19 +119,20 @@ void va_space_create(struct va_space *vs, struct pa_space *ps, uint64_t dtb)
     va_space_set_dtb(vs, dtb);
 }
 
-static uint64_t get_pml4e(struct va_space *vs, uint64_t va)
+static bool get_pml4e(struct va_space *vs, uint64_t va, uint64_t *value)
 {
     uint64_t pa = (vs->dtb & 0xffffffffff000) | ((va & 0xff8000000000) >> 36);
 
-    return *(uint64_t *)pa_space_resolve(vs->ps, pa);
+    return pa_space_read64(vs->ps, pa, value);
 }
 
-static uint64_t get_pdpi(struct va_space *vs, uint64_t va, uint64_t pml4e)
+static bool get_pdpi(struct va_space *vs, uint64_t va, uint64_t pml4e,
+                    uint64_t *value)
 {
     uint64_t pdpte_paddr = (pml4e & 0xffffffffff000) |
         ((va & 0x7FC0000000) >> 27);
 
-    return *(uint64_t *)pa_space_resolve(vs->ps, pdpte_paddr);
+    return pa_space_read64(vs->ps, pdpte_paddr, value);
 }
 
 static uint64_t pde_index(uint64_t va)
@@ -131,11 +145,12 @@ static uint64_t pdba_base(uint64_t pdpe)
     return pdpe & 0xFFFFFFFFFF000;
 }
 
-static uint64_t get_pgd(struct va_space *vs, uint64_t va, uint64_t pdpe)
+static bool get_pgd(struct va_space *vs, uint64_t va, uint64_t pdpe,
+                   uint64_t *value)
 {
     uint64_t pgd_entry = pdba_base(pdpe) + pde_index(va) * 8;
 
-    return *(uint64_t *)pa_space_resolve(vs->ps, pgd_entry);
+    return pa_space_read64(vs->ps, pgd_entry, value);
 }
 
 static uint64_t pte_index(uint64_t va)
@@ -148,11 +163,12 @@ static uint64_t ptba_base(uint64_t pde)
     return pde & 0xFFFFFFFFFF000;
 }
 
-static uint64_t get_pte(struct va_space *vs, uint64_t va, uint64_t pgd)
+static bool get_pte(struct va_space *vs, uint64_t va, uint64_t pgd,
+                   uint64_t *value)
 {
     uint64_t pgd_val = ptba_base(pgd) + pte_index(va) * 8;
 
-    return *(uint64_t *)pa_space_resolve(vs->ps, pgd_val);
+    return pa_space_read64(vs->ps, pgd_val, value);
 }
 
 static uint64_t get_paddr(uint64_t va, uint64_t pte)
@@ -184,13 +200,11 @@ static uint64_t va_space_va2pa(struct va_space *vs, uint64_t va)
 {
     uint64_t pml4e, pdpe, pgd, pte;
 
-    pml4e = get_pml4e(vs, va);
-    if (!is_present(pml4e)) {
+    if (!get_pml4e(vs, va, &pml4e) || !is_present(pml4e)) {
         return INVALID_PA;
     }
 
-    pdpe = get_pdpi(vs, va, pml4e);
-    if (!is_present(pdpe)) {
+    if (!get_pdpi(vs, va, pml4e, &pdpe) || !is_present(pdpe)) {
         return INVALID_PA;
     }
 
@@ -198,8 +212,7 @@ static uint64_t va_space_va2pa(struct va_space *vs, uint64_t va)
         return get_1GB_paddr(va, pdpe);
     }
 
-    pgd = get_pgd(vs, va, pdpe);
-    if (!is_present(pgd)) {
+    if (!get_pgd(vs, va, pdpe, &pgd) || !is_present(pgd)) {
         return INVALID_PA;
     }
 
@@ -207,8 +220,7 @@ static uint64_t va_space_va2pa(struct va_space *vs, uint64_t va)
         return get_2MB_paddr(va, pgd);
     }
 
-    pte = get_pte(vs, va, pgd);
-    if (!is_present(pte)) {
+    if (!get_pte(vs, va, pgd, &pte) || !is_present(pte)) {
         return INVALID_PA;
     }