From 8f99c43384b9122eedeab1411ab5076ca5878ef9 Mon Sep 17 00:00:00 2001 From: Lidong Chen Date: Fri, 22 Nov 2024 06:27:58 +0000 Subject: [PATCH 04/20] fs/tar: Integer overflow leads to heap OOB write Both namesize and linksize are derived from hd.size, a 12-digit octal number parsed by read_number(). Later direct arithmetic calculation like "namesize + 1" and "linksize + 1" may exceed the maximum value of grub_size_t leading to heap OOB write. This patch fixes the issue by using grub_add() and checking for an overflow. Fixes: CVE-2024-45780 Reported-by: Nils Langius Signed-off-by: Lidong Chen Reviewed-by: Daniel Kiper Reviewed-by: Alec Brown --- grub-core/fs/tar.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) diff --git a/grub-core/fs/tar.c b/grub-core/fs/tar.c index c551ed6b52..a9e39b0eb6 100644 --- a/grub-core/fs/tar.c +++ b/grub-core/fs/tar.c @@ -25,6 +25,7 @@ #include #include #include +#include GRUB_MOD_LICENSE ("GPLv3+"); @@ -76,6 +77,7 @@ grub_cpio_find_file (struct grub_archelp_data *data, char **name, { struct head hd; int reread = 0, have_longname = 0, have_longlink = 0; + grub_size_t sz; data->hofs = data->next_hofs; @@ -97,7 +99,11 @@ grub_cpio_find_file (struct grub_archelp_data *data, char **name, { grub_err_t err; grub_size_t namesize = read_number (hd.size, sizeof (hd.size)); - *name = grub_malloc (namesize + 1); + + if (grub_add (namesize, 1, &sz)) + return grub_error (GRUB_ERR_BAD_FS, N_("name size overflow")); + + *name = grub_malloc (sz); if (*name == NULL) return grub_errno; err = grub_disk_read (data->disk, 0, @@ -117,15 +123,19 @@ grub_cpio_find_file (struct grub_archelp_data *data, char **name, { grub_err_t err; grub_size_t linksize = read_number (hd.size, sizeof (hd.size)); - if (data->linkname_alloc < linksize + 1) + + if (grub_add (linksize, 1, &sz)) + return grub_error (GRUB_ERR_BAD_FS, N_("link size overflow")); + + if (data->linkname_alloc < sz) { char *n; - n = grub_calloc (2, linksize + 1); + n = grub_calloc (2, sz); if (!n) return grub_errno; grub_free (data->linkname); data->linkname = n; - data->linkname_alloc = 2 * (linksize + 1); + data->linkname_alloc = 2 * (sz); } err = grub_disk_read (data->disk, 0, @@ -148,7 +158,10 @@ grub_cpio_find_file (struct grub_archelp_data *data, char **name, while (extra_size < sizeof (hd.prefix) && hd.prefix[extra_size]) extra_size++; - *name = grub_malloc (sizeof (hd.name) + extra_size + 2); + + if (grub_add (sizeof (hd.name) + 2, extra_size, &sz)) + return grub_error (GRUB_ERR_BAD_FS, N_("long name size overflow")); + *name = grub_malloc (sz); if (*name == NULL) return grub_errno; if (hd.prefix[0]) -- 2.48.1