linux-kernel - [PATCH] alpha: kernel: module: Adding branch statements after allocating memory for kmalloc

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Message-Id: <20230325192530.3298-1-kunyu@nfschina.com>
Date:   Sun, 26 Mar 2023 03:25:30 +0800
From:   Li kunyu <kunyu@...china.com>
To:     richard.henderson@...aro.org, ink@...assic.park.msu.ru,
        mattst88@...il.com, aurxenon@...os.org
Cc:     linux-kernel@...r.kernel.org, Li kunyu <kunyu@...china.com>
Subject: [PATCH] alpha: kernel: module: Adding branch statements after allocating memory for kmalloc

After looking at the process_reloc_for_got function and where it is
called, I decided to use a branch statement to increase the robustness
of the pointer g.

If pointer g allocation fails, when 'chains [i]. next' is executed, it
can avoid crashes caused by wild pointers.

Signed-off-by: Li kunyu <kunyu@...china.com>
---
 arch/alpha/kernel/module.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/alpha/kernel/module.c b/arch/alpha/kernel/module.c
index cbefa5a77384..8c97f10347a7 100644
--- a/arch/alpha/kernel/module.c
+++ b/arch/alpha/kernel/module.c
@@ -47,11 +47,15 @@ process_reloc_for_got(Elf64_Rela *rela,
 		}
 
 	g = kmalloc (sizeof (*g), GFP_KERNEL);
-	g->next = chains[r_sym].next;
-	g->r_addend = r_addend;
-	g->got_offset = *poffset;
-	*poffset += 8;
-	chains[r_sym].next = g;
+	if (g) {
+		g->next = chains[r_sym].next;
+		g->r_addend = r_addend;
+		g->got_offset = *poffset;
+		*poffset += 8;
+		chains[r_sym].next = g;
+	}
+	else
+		chains[r_sym].next = NULL;
 
  found_entry:
 	/* Trick: most of the ELF64_R_TYPE field is unused.  There are
-- 
2.18.2