[bug #63894] grub_datetime2unixtime() still has the year 2038 problem.

[Masayuki Moriyama]

URL:
  <https://savannah.gnu.org/bugs/?63894>

                 Summary: grub_datetime2unixtime() still has the year 2038
problem.
                   Group: GNU GRUB
               Submitter: moriyama
               Submitted: Wed 08 Mar 2023 11:04:29 AM UTC
                Category: Filesystem
                Severity: Major
                Priority: 5 - Normal
              Item Group: Software Error
                  Status: None
                 Privacy: Public
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
                 Release: Git master
                 Release: 
         Discussion Lock: Any
         Reproducibility: Every Time
         Planned Release: None


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Follow-up Comments:


-------------------------------------------------------
Date: Wed 08 Mar 2023 11:04:29 AM UTC By: Masayuki Moriyama <moriyama>
I found two problems in the grub_datetime2unixtime() function.

*Problem 1:*
The grub_datetime2unixtime() function returns a 64-bit integer unixtime as the
second argument, but the variable used for internal calculation is a 32-bit
integer variable.

*Problem 2:*
Year exceeding the unixtime 32-bit integer value is regarded as an error.


include/grub/datetime.h
<https://git.savannah.gnu.org/cgit/grub.git/tree/include/grub/datetime.h?id=88478417315b652850e36ff7f3f63f6bcf399e84>:

 54 static inline int
 55 grub_datetime2unixtime (const struct grub_datetime *datetime, grub_int64_t
*nix)
 56 {
 57   grub_int32_t ret; <= Problem 1: 32bit integer
...snip...
 80   if (datetime->year > 2038 || datetime->year < 1901) <= Problem 2: Year
exceeding the unixtime 32-bit integer value is regarded as an error
 81     return 0;
...snip...
122   *nix = ret; <= Assign 32-bit integer value to 64-bit integer variable
123   return 1;


Due to these problems, the "grub-probe --device DEVICE --target=fs" command
cannot recognize the FAT file system if there are directories or files dated
after January 19, 2038 in the / directory of the FAT file system.

*Steps to Reproduce:*

Run on Fedora 36 Workstation Live image
<https://ftp.riken.jp/Linux/fedora/releases/36/Workstation/x86_64/iso/Fedora-Workstation-Live-x86_64-36-1.5.iso>.


# fallocate -l 100m fat32.img
# LOOPDEV=$(losetup --show -f fat32.img)
# mkdosfs -F 32 $LOOPDEV
# mkdir -p /mnt/fat32
# mount $LOOPDEV /mnt/fat32
# mkdir /mnt/fat32/EFI
# touch -d "2040-01-01" /mnt/fat32/EFI
# grub2-probe --version
grub2-probe (GRUB) 2.06
# grub2-probe --device $LOOPDEV --target=fs
grub2-probe: error: ../grub-core/kern/fs.c:120:unknown filesystem.


Fedora 37 Workstation Live image
<https://download.fedoraproject.org/pub/fedora/linux/releases/37/Workstation/x86_64/iso/Fedora-Workstation-Live-x86_64-37-1.7.iso>
does not reproduce any problems because commit
e43f3d93b28cce852c110c7a8e40d8311bcd8bb1
<https://git.savannah.gnu.org/cgit/grub.git/commit/grub-core/fs?id=e43f3d93b28cce852c110c7a8e40d8311bcd8bb1>
(fs/fat: Don't error when mtime is 0) is applied.








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