bd8434f4f4
Hi @tiann. Thanks for the great project, I had great fun playing around with it. This PR mainly tries to further minimize the possible delays caused by KernelSU hooking. There are 3 major changes: - Processes with 0 < UID < 2000 are blocked straight-up before going through the allow_list. I don't see any need for such processes to be interested in root, and this allows returning early before going through a more expensive lookup. If there's an expected breakage due to this change, I'll remove it. Let me know. - A page-sized (4K) bitmap is added. This allows O(1) lookup for UID <= 32767. This speeds up `ksu_is_allow_uid()` by about 4.8x by sacrificing a 4K memory. IMHO, a good trade-off. Most notably, this reduces the 99.999% result previously from worrying milliseconds scale to microseconds scale. For UID > 32767, another page-sized (4K) sequential array is used to cache allow_list. Compared to the previous PR #557, this new approach gives another nice 25% performance boost in average, 63-96% boost in worst cases. Benchmark results are available at https://docs.google.com/spreadsheets/d/1w_tO1zRLPNMFRer49pL1TQfL6ndEhilRrDU1XFIcWXY/edit?usp=sharing Thanks! --------- Signed-off-by: Juhyung Park <qkrwngud825@gmail.com>
35 lines
971 B
C
35 lines
971 B
C
#include "linux/version.h"
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#include "linux/fs.h"
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#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 10, 0)
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#include "linux/key.h"
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#include "linux/errno.h"
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struct key *init_session_keyring = NULL;
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#endif
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ssize_t ksu_kernel_read_compat(struct file *p, void *buf, size_t count, loff_t *pos){
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#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 14, 0)
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return kernel_read(p, buf, count, pos);
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#else
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loff_t offset = pos ? *pos : 0;
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ssize_t result = kernel_read(p, offset, (char *)buf, count);
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if (pos && result > 0)
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{
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*pos = offset + result;
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}
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return result;
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#endif
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}
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ssize_t ksu_kernel_write_compat(struct file *p, const void *buf, size_t count, loff_t *pos){
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#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 14, 0)
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return kernel_write(p, buf, count, pos);
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#else
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loff_t offset = pos ? *pos : 0;
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ssize_t result = kernel_write(p, buf, count, offset);
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if (pos && result > 0)
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{
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*pos = offset + result;
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}
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return result;
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#endif
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}
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