Messages in this thread Patches in this message |  | | Date | Sun, 19 Nov 2000 04:07:04 +0100 | From | Andrea Arcangeli <> | Subject | Re: lseek/llseek allows the negative offset |
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On Sat, Nov 18, 2000 at 05:20:34PM -0800, H . J . Lu wrote: > Try this again 2.2.18pre21. It works for me. > > > -- > H.J. Lu (hjl@valinux.com) > --- > --- linux/fs/ext2/file.c.lseek Sat Nov 18 17:18:49 2000 > +++ linux/fs/ext2/file.c Sat Nov 18 17:19:28 2000 > @@ -120,6 +120,8 @@ static long long ext2_file_lseek( > case 1: > offset += file->f_pos; > } > + if (offset < 0) > + return -EINVAL; > if (((unsigned long long) offset >> 32) != 0) { > #if BITS_PER_LONG < 64 > return -EINVAL;
It's not enough for 2.2.x (and you left the `>> 32' nosense check).
2.2.x vanilla (so non-lfs) is getting wrong both 32bit and 64bit:
1) 32bit can lseek over 2G and it can return bogus retval
main() { int fd = creat("x", 0600); lseek(fd, 0x7fffffff, 1); lseek(fd, 0x7fffffff, 1); }
lseek(3, 2147483647, SEEK_CUR) = 2147483647 lseek(3, 2147483647, SEEK_CUR) = -1 ENOENT (No such file or directory)
(this isn't really -ENOENT but it's just trying to return a succesful -2 value)
2) 64bit can lseek over ext2_max_sizes and it can return bogus retvals
main() { int fd = creat("x", 0600); lseek(fd, -2, 0); }
open("x", O_WRONLY|O_CREAT|O_TRUNC, 0600) = 3 lseek(3, 18446744073709551614, SEEK_SET) = -1 ENOENT (No such file or directory)
(this isn't really -ENOENT but it's just trying to return a succesful -2 value)
This will cure 2.2.x vanilla:
--- 2.2.18pre21/fs/ext2/file.c.~1~ Sun Nov 12 00:45:42 2000 +++ 2.2.18pre21/fs/ext2/file.c Sun Nov 19 03:59:29 2000 @@ -120,14 +120,14 @@ case 1: offset += file->f_pos; } - if (((unsigned long long) offset >> 32) != 0) { #if BITS_PER_LONG < 64 + if (offset >> 31) return -EINVAL; #else - if (offset > ext2_max_sizes[EXT2_BLOCK_SIZE_BITS(inode->i_sb)]) - return -EINVAL; + if (offset < 0 || + offset > ext2_max_sizes[EXT2_BLOCK_SIZE_BITS(inode->i_sb)]) + return -EINVAL; #endif - } if (offset != file->f_pos) { file->f_pos = offset; file->f_reada = 0; and this will remove the nosense stuff from 2.4.x:
--- 2.4.0-test11-pre6/fs/ext2/file.c.~1~ Thu Nov 16 15:37:32 2000 +++ 2.4.0-test11-pre6/fs/ext2/file.c Sun Nov 19 04:03:27 2000 @@ -53,12 +53,9 @@ case 1: offset += file->f_pos; } - if (offset<0) + if (offset < 0 || + offset > ext2_max_sizes[EXT2_BLOCK_SIZE_BITS(inode->i_sb)]) return -EINVAL; - if (((unsigned long long) offset >> 32) != 0) { - if (offset > ext2_max_sizes[EXT2_BLOCK_SIZE_BITS(inode->i_sb)]) - return -EINVAL; - } if (offset != file->f_pos) { file->f_pos = offset; file->f_reada = 0; (the above is also ok for 2.2.x-lfs and I'll fix it that way)
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