mm/early_ioremap: add null pointer checks to prevent NULL-pointer dereference

The early_ioremap interface can fail and return NULL in certain cases.  To
prevent NULL-pointer dereference crashes, fixed issues in the acpi_extlog
and copy_early_mem interfaces, improving robustness when handling early
memory.

Link: https://lkml.kernel.org/r/20241212101004.1544070-1-guoweikang.kernel@gmail.com
Signed-off-by: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Julian Stecklina <julian.stecklina@cyberus-technology.de>
Cc: Kevin Loughlin <kevinloughlin@google.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Xin Li (Intel) <xin@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index f1fea506e20f417bdb6d27c98f7f9919c87533b2..cebee310e2009efa7cbcb64f6f841995940166d7 100644 (file)
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -259,6 +259,7 @@ static void __init relocate_initrd(void)
        u64 ramdisk_image = get_ramdisk_image();
        u64 ramdisk_size  = get_ramdisk_size();
        u64 area_size     = PAGE_ALIGN(ramdisk_size);
+       int ret = 0;
 
        /* We need to move the initrd down into directly mapped mem */
        u64 relocated_ramdisk = memblock_phys_alloc_range(area_size, PAGE_SIZE, 0,
@@ -272,7 +273,9 @@ static void __init relocate_initrd(void)
        printk(KERN_INFO "Allocated new RAMDISK: [mem %#010llx-%#010llx]\n",
               relocated_ramdisk, relocated_ramdisk + ramdisk_size - 1);
 
-       copy_from_early_mem((void *)initrd_start, ramdisk_image, ramdisk_size);
+       ret = copy_from_early_mem((void *)initrd_start, ramdisk_image, ramdisk_size);
+       if (ret)
+               panic("Copy RAMDISK failed\n");
 
        printk(KERN_INFO "Move RAMDISK from [mem %#010llx-%#010llx] to"
                " [mem %#010llx-%#010llx]\n",

diff --git a/drivers/acpi/acpi_extlog.c b/drivers/acpi/acpi_extlog.c
index ca87a093913599ea4681c0179ea2c6a85e18bfb3..f7fb7205028db19559a86e05cbf30c3cb00f722e 100644 (file)
--- a/drivers/acpi/acpi_extlog.c
+++ b/drivers/acpi/acpi_extlog.c
@@ -251,6 +251,10 @@ static int __init extlog_init(void)
        }
 
        extlog_l1_hdr = acpi_os_map_iomem(l1_dirbase, l1_hdr_size);
+       if (!extlog_l1_hdr) {
+               rc = -ENOMEM;
+               goto err_release_l1_hdr;
+       }
        l1_head = (struct extlog_l1_head *)extlog_l1_hdr;
        l1_size = l1_head->total_len;
        l1_percpu_entry = l1_head->entries;
@@ -268,6 +272,10 @@ static int __init extlog_init(void)
                goto err;
        }
        extlog_l1_addr = acpi_os_map_iomem(l1_dirbase, l1_size);
+       if (!extlog_l1_addr) {
+               rc = -ENOMEM;
+               goto err_release_l1_dir;
+       }
        l1_entry_base = (u64 *)((u8 *)extlog_l1_addr + l1_hdr_size);
 
        /* remap elog table */
@@ -279,6 +287,10 @@ static int __init extlog_init(void)
                goto err_release_l1_dir;
        }
        elog_addr = acpi_os_map_iomem(elog_base, elog_size);
+       if (!elog_addr) {
+               rc = -ENOMEM;
+               goto err_release_elog;
+       }
 
        rc = -ENOMEM;
        /* allocate buffer to save elog record */
@@ -300,6 +312,8 @@ err_release_l1_dir:
        if (extlog_l1_addr)
                acpi_os_unmap_iomem(extlog_l1_addr, l1_size);
        release_mem_region(l1_dirbase, l1_size);
+err_release_l1_hdr:
+       release_mem_region(l1_dirbase, l1_hdr_size);
 err:
        pr_warn(FW_BUG "Extended error log disabled because of problems parsing f/w tables\n");
        return rc;

diff --git a/include/asm-generic/early_ioremap.h b/include/asm-generic/early_ioremap.h
index 9d0479f50f97f4c1b9cd717253d342c7ed2cd57e..5db59a1efb65757da5223d49314c594ad2c5e7fe 100644 (file)
--- a/include/asm-generic/early_ioremap.h
+++ b/include/asm-generic/early_ioremap.h
@@ -35,7 +35,7 @@ extern void early_ioremap_reset(void);
 /*
  * Early copy from unmapped memory to kernel mapped memory.
  */
-extern void copy_from_early_mem(void *dest, phys_addr_t src,
+extern int copy_from_early_mem(void *dest, phys_addr_t src,
                                unsigned long size);
 
 #else

diff --git a/mm/early_ioremap.c b/mm/early_ioremap.c
index ce06b2884789a2bd97016b93916c8aa81dc288b7..ff35b84a7b5081a4e0e3ba29e7d4d5339b4e2e27 100644 (file)
--- a/mm/early_ioremap.c
+++ b/mm/early_ioremap.c
@@ -245,7 +245,10 @@ early_memremap_prot(resource_size_t phys_addr, unsigned long size,
 
 #define MAX_MAP_CHUNK  (NR_FIX_BTMAPS << PAGE_SHIFT)
 
-void __init copy_from_early_mem(void *dest, phys_addr_t src, unsigned long size)
+/*
+ * If no empty slot, handle that and return -ENOMEM.
+ */
+int __init copy_from_early_mem(void *dest, phys_addr_t src, unsigned long size)
 {
        unsigned long slop, clen;
        char *p;
@@ -256,12 +259,15 @@ void __init copy_from_early_mem(void *dest, phys_addr_t src, unsigned long size)
                if (clen > MAX_MAP_CHUNK - slop)
                        clen = MAX_MAP_CHUNK - slop;
                p = early_memremap(src & PAGE_MASK, clen + slop);
+               if (!p)
+                       return -ENOMEM;
                memcpy(dest, p + slop, clen);
                early_memunmap(p, clen + slop);
                dest += clen;
                src += clen;
                size -= clen;
        }
+       return 0;
 }
 
 #else /* CONFIG_MMU */