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From 1c14a6d8ebad07bc6ff090164ca15ab7656e7167 Mon Sep 17 00:00:00 2001
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From: Ido Schimmel <idosch@nvidia.com>
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Date: Tue, 14 Sep 2021 14:27:35 +0300
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Subject: [PATCH 02/35] cmis: Fix invalid memory access in IOCTL path
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Page 01h is an optional page that is not available for flat memory
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modules. Trying to blindly access it results in the following report
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from AddressSanitizer [1].
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Instead, pass the base address of the Lower Memory. This results in
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wrong information being parsed, but this never worked correctly since
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CMIS support first appeared in cited commit.
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The information will be parsed correctly in a follow-up submission that
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reworks the EEPROM parsing code to use a memory map with pointers to
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individual pages instead of passing one large buffer.
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[1]
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==968785==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x6120000001d4 at pc 0x0000004806ee bp 0x7ffefbc977a0 sp 0x7ffefbc97798
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READ of size 1 at 0x6120000001d4 thread T0
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    #0 0x4806ed in cmis_print_smf_cbl_len cmis.c:127
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    #1 0x48113e in cmis_show_link_len_from_page cmis.c:279
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    #2 0x4811e3 in cmis_show_link_len cmis.c:300
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    #3 0x481358 in qsfp_dd_show_all cmis.c:336
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    #4 0x47d190 in sff8636_show_all qsfp.c:861
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    #5 0x42130b in do_getmodule ethtool.c:4908
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    #6 0x42a38a in main ethtool.c:6383
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    #7 0x7f11db6c51e1 in __libc_start_main (/lib64/libc.so.6+0x281e1)
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    #8 0x40258d in _start (ethtool+0x40258d)
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Address 0x6120000001d4 is a wild pointer.
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SUMMARY: AddressSanitizer: heap-buffer-overflow cmis.c:127 in cmis_print_smf_cbl_len
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Fixes: 88ca347ef35a ("Add QSFP-DD support").
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Signed-off-by: Ido Schimmel <idosch@nvidia.com>
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---
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 cmis.c | 2 +-
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 1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/cmis.c b/cmis.c
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index 361b721f332f..1a91e798e4b8 100644
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--- a/cmis.c
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+++ b/cmis.c
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@@ -297,7 +297,7 @@ static void cmis_show_link_len_from_page(const __u8 *page_one_data)
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  */
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 static void cmis_show_link_len(const __u8 *id)
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 {
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-	cmis_show_link_len_from_page(id + PAG01H_UPPER_OFFSET);
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+	cmis_show_link_len_from_page(id);
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 }
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 /**
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-- 
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2.35.1
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